Model Boat Mayhem - Forum

Technical, Techniques, Hints, and Tips => Microprocessor control => Topic started by: Bob K on December 23, 2016, 10:48:31 AM

Title: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on December 23, 2016, 10:48:31 AM
A technical quandary.  How to simultaneously rotate seven main armament gun turrets. 
Some of you may guess what ship this is for.

To get more than 180 degrees rotation on a turret I will need a servo plus a control arm to increase the angle over the normal of about 90 degrees.  It would be nice to slow the rotation down, if possible.
It may be possible to rotate two adjacent turrets from one servo by adding linkages, but trying to add enough servos to a single receiver channel will be far too much load for the Rx, even with splitter leads which do not reduce the channel loading.

Any ideas ?

Title: Re: Rotating seven gun turrets?
Post by: Tug-Kenny on December 23, 2016, 10:54:15 AM

Two things spring to mind here with your question, Bob.

Would this normally be seen in action on the real ship and also how close are they together  ?

My first reaction was a rubber drive belt. Is this any good. ?

ken
 
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 23, 2016, 11:08:16 AM
Thanks Ken.

Seven centreline turrets spread along around four and a half feet of a seven foot dreadnaught, made more complicated by my needing to split the hull in half for transport.  3 in the front half, 4 in the rear.
I realise that turrets do not train in exact unison, but achieving that effect may be a bridge too far.  ie: building in short time delays.
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 23, 2016, 11:14:45 AM
 :-)) :-)) :-)) :-)) :-)) :-)) :-)) :-)) :-)) :-)) :-)) :-)) :-)) :-)) :-)) %%

Obviously there are going to be several ways to do the movement you require of the gun turrets - I can suggest a couple of ways I achieved this on 2 or 3 models - the first way I did it:

on HMS Ajax - I had 3 old Futaba Servos (they were the very old ones) which I stripped the electronics from and this left only the motor and the gearing.    I also removed the physical stops from the plastic casings of the servos - so that the 3 servos could rotate.   Then I purchased a new Futaba servo, opened it, and soldered onto it 2 fly-lead wires from the contacts of the motor.  These 2 fly-leads from this servo, which was to become the main lead servo - were wired up to the three old servos in parallel, so, basically the 3 servo motors would mimic what the first brand new servo would do.  Then, the other thing I had to do was to modify the new servo by taking the variable resistance pot out and adding 2 resistors.   This isn't as complicated as it sounds and there are plenty of videos on YouTube, which show you how to do this.  Each servo was mounted underneath a gun turret - the only problem with this is that sometimes the gun turrets do not line up on the centre line.

the second way I did it on HMS Exeter was I purchased 2 servo stretchers from Technobots and 1 from ACTion:   These were mounted obviously in the hull and connected to 3 standard servos, which in turn were mounted underneath each individual turret.  This was the easiest solution I have found, with the least problems.   

The bugbear is (and it doesn't matter which system you use) the low speed of the turn of the turrets tends to produce a jerky movement.   

If you look at my HMS Exeter build there is a section there where the turret build is explained.

http://www.modelboatmayhem.co.uk/forum/index.php/topic,33734.75.html

john





Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 23, 2016, 01:08:47 PM
Lovely build.  Very interesting  :-))

But how to I couple seven servos to one receiver channel ?
Title: Re: Rotating seven gun turrets?
Post by: Netleyned on December 23, 2016, 01:36:32 PM
Using two sail drum servos and Kenny's
Elastic Band  with a Y lead connected
between the two hull sections might
work from one channel Bob.
Not tried it myself, just a suggestion.


Ned
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 23, 2016, 02:07:31 PM
Hi ya Bob, what model is this actually for?    I have had a quick look through your postings to see if I could see which model this would be for, but, I am unsure?

Generally speaking though on a warship, not all the turrets will turn at the same time.  Also, they will not all be pointing in the same direction - there will only be a select amount of guns which point outwards at the same time.   If the guns on the starboard side of the ship are facing outboard/starboard - the guns on the portside wouldn't (I am sure) traverse and fire across deck - they would stay in a fore and aft position.

Really, you should be using 2 channels for your gun movements and these 2 channels could be split with Y leads accordingly.   

I did forget to mention, I added the Y leads before the servo slowers - also, I used 2 channels.

John
Title: Re: Rotating seven gun turrets?
Post by: Netleyned on December 23, 2016, 02:29:11 PM
He's got Deans Marineitis :D
Seen the new Grey Machine
and fallen for it.
Its bigger than his car so
a split hull is needed.
Ned
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 23, 2016, 02:35:35 PM
Hello John,  I intend building one of these during 2017.  Correct Ned - Yes, I am crazy.  Over 7 ft long

http://www.modelboatmayhem.co.uk/forum/index.php/topic,56290.msg584168.html#msg584168 (http://www.modelboatmayhem.co.uk/forum/index.php/topic,56290.msg584168.html#msg584168)

I looked up servo slowers, they use them for model aircraft landing gear retract.  Bookmarked it. 
http://modelradioworkshop.co.uk/shop/servo-control-devices/5-servo-turret-controller/ (http://modelradioworkshop.co.uk/shop/servo-control-devices/5-servo-turret-controller/)
Thanks.
I guess I can have one slower per turret or pair, slightly different timings, to bring all guns to a broadside firing position.  Guns barrels raising using a guide inside turrets. 
Title: Re: Rotating seven gun turrets?
Post by: plastic on December 23, 2016, 03:55:21 PM
With that number at that scale, I'd be putting a little dc motor in each turret with microswitch & diode travel limits - with gearboxes, you can make them move nice & slow. Drive them all from a single speed controller so they all track at the same speed - they would synchronise position when they all reach an endstop.
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 23, 2016, 04:39:45 PM
Lovely build.  Very interesting  :-))

But how to I couple seven servos to one receiver channel ?
Arduino would be my first choice, and use miniature geared steppers instead of servos.


Andy
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 23, 2016, 04:50:16 PM
Hi Andy

What we must remember is not everyone is capable of programming and writing software for these systems.   Some people, including me, prefer to keep it as simple as possible to understand  :-) .

I appreciate where you are coming from though but also we have to remember stuff like this does literally terrify some people  %% %%

John
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 23, 2016, 05:17:37 PM
I rather think that any electro mechanical system will struggle to keep seven turrets accurately synchronised, particularly in returning them to a properly aligned fore and aft heading. Maybe each of the three turret groups could have its own 'gearbox' though. But then again you have to take into account the fact that the different turrets all had their own training arcs, point in different directions when at rest and not all would fire on the same bearings.

Logically Andy is right. The turrets should be computer controlled. You would send a signal to the model stipulating the target bearing and then each turret would need to 'decide' whether it could achieve that bearing and, if so, train round to it. Of course this would take no account of the movement of the model itself which would require another level of computation to keep the guns bearing entailing comparison of the target bearing with the ship's heading. An interesting programming problem!

I think the most you could realistically achieve with a simple system is three positions: 1: turrets aligned with the ship's keel; 2: trained out 90 degrees to starboard and 3: trained out 90 degrees to port.

Colin
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 23, 2016, 05:38:05 PM
hi there Colin

There was no way I was trying to run Andy's system down.   I was just trying to put it into perspective for everyone on the Forum.    If someone was to design and build a module; similar to a receiver, where you plugged in say several motors or servos; and you could make adjustments and it was pre-programmed similar to what Andy is describing - that would suit a lot of people.   When you think about the average model boater and this is coming from reading this forum, they struggle with where to put a fuse in the electrical system of the model; they struggle about how to wire speed controllers up and in general they struggle with electronics.

 You mention only obtaining 3 points of movement of the guns - to be honest with you - if we had more control over the positions of the guns - who would really notice, apart from those controlling the model and those who knew about the electronics inside the model, but the average onlooker from the public would think 'oh look at Bismark's guns turning, and hey Mr is that the Titanic'.

John
Title: Re: Rotating seven gun turrets?
Post by: barriew on December 23, 2016, 05:51:25 PM
Providing you will have the capability of multiple links between the two halves of the hull (servo leads) there are a number of people on Mayhem who I am sure could provide an Arduino based solution (including me) and I think it would cost less than £20. This would also provide power for each servo independent of the Rx battery.
The only problem I would have is having that number of servos to do the testing.
Barrie
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 23, 2016, 05:55:59 PM
John, I appreciate what you are saying but my feeling is that the geometry of all those turrets is a bit of a nightmare unless you just want to do something simple. Unlike the relative simplicity of say, a Queen Elizabeth class with two forward turrets and two aft, the Agincourt has the two forward turrets pointing in one direction, the middle two at 180 degrees to each other and one of the aft turrets pointing in the opposite direction to the other two. The only thing they all have in common is that they can train on either broadside and I reckon that would be easier to achieve than trying to make them line up on intermediate bearings. As you quite rightly say, the simple fact that they can move and all point in the same direction on one broadside or the other would be pretty effective visually. Having the barrels automatically elevate using guides would enhance the effect as long as you don't knock the flying bridge off!

Even so, it would still be quite a fiddly job and I reckon you would need one mechanism for the forward two turrets, two for the middle two (although you could introduce a linked contra rotation maybe) and another two for the after group.

As said previously, the mechanisms would need to have a good degree of mechanical and electronic (servo) precision with no backlash to ensure that the guns are correctly aligned in the three stop positions.

It's not impossible but anyone attempting to do this needs to understand that there is no quick fix! Some pretty precise model engineering and a good working knowledge of servos systems is a basic requirement even without venturing into the realms of computerisation.

Colin
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 23, 2016, 06:59:21 PM
Andy, I have followed your Arduino info with interest, but I don't think programming them is within my personal ability.  I have seen a ship train her guns to a relative bearing, and adjust aim as it turns, but that requires some serious computer control.  Especially when one or more reaches it's maximum arc of fire.

Just to make life interesting, in order to split this massive hull for transport I need to cut it between the centre two turrets under the flying bridges.  Three turrets in the forward half, four in the rear.

Many thanks everyone.  Certainly some good food for thought.  I would be happy just to train them all 90 degrees to port or starboard, with barrels elevating using ramps/guides.  Plenty of room inside for a gunfire sound system, maybe LED's in the barrels.  I would stop short of smoke effects though ( Tee hee ).

What makes this ship impressive is the sheer quantity of turrets, so I would like to show them off if I can 

 
Title: Re: Rotating seven gun turrets?
Post by: unbuiltnautilus on December 23, 2016, 07:07:49 PM
Right, first thoughts..KISS. Treat the fore and aft sections as separate models. Put a receiver in both the fore and aft sections, both bound to the same transmitter. Plug your turret gizmos, morphs or whatever, into the same channel on both receivers. This will reduce the load as you will have either three or four servos only per hull, connected to your individual receivers. This also eliminates any awkward hull plug connections, also eliminating any access holes having to be waterproofed. I followed this route on SS Ohio, two Rx's with only one Tx.
Servo chatter as you slow the output down could be a bit of an issue, as could re-aligning on the centre line after broadsides, but that's what modelling is all about!
I could show you a turret rotation mechanism with seven stop positions, using micro switches, working through a bank of relays. Very effective, but a pig to make. Servos, nice and easy :-))
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 23, 2016, 07:31:50 PM
Hi John - not feeling 'run down' at all. More like 'fired up'.  O0


I'll start a new thread after Christmas & the New Year. Cheap, easy and accurate microprocessor fire control.


Andy
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 23, 2016, 09:12:25 PM
Right, first thoughts..KISS. Treat the fore and aft sections as separate models. Put a receiver in both the fore and aft sections, both bound to the same transmitter. Plug your turret gizmos, morphs or whatever, into the same channel on both receivers. This will reduce the load as you will have either three or four servos only per hull, connected to your individual receivers. This also eliminates any awkward hull plug connections, also eliminating any access holes having to be waterproofed. I followed this route on SS Ohio, two Rx's with only one Tx.

Now that is a good idea -  2 x receivers. 
KISS indeed.  It will also give the big SLA ballast in the fore part something to do.
Title: Re: Rotating seven gun turrets?
Post by: RAAArtyGunner on December 23, 2016, 11:11:52 PM
Hi Andy

What we must remember is not everyone is capable of programming and writing software for these systems.   Some people, including me, prefer to keep it as simple as possible to understand  :-) .

I appreciate where you are coming from though but also we have to remember stuff like this does literally terrify some people  %% %%

John

Yes  :-)) :-))


Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 23, 2016, 11:15:53 PM
Bob...this is a very interesting scenario.....however in todays world the direction of the movement of the turrets in the thread is heading toward a controlled precise ballet symphony

The vessel did have state of the art for the day gun control systems [an Officer in the Crows Nest {-) ] relaying messages to a Senior Weapons Officer in the Fire Control Bunker....who would relay these massages to the Captain......so eventually a command is given to each Gun Captain to train and elevate the mount to the directed positions

I suggest the turrets in their day would not have resembled the orchestrated ballet movement of today

As previously suggested, each turret having the ability to very slowly train and elevate to an athwart or midships position and return to the in line home position would suffice.... and be far more realistic  O0

The elevation could be via a fixed spring loaded cam within each turret and require no electrical of mechanical input

Certainly a few [3] ACTion P96 controllers and some Y leads would provide the progressive slow speed and also the final set points for turret train, and the return home position

Derek   
Title: Re: Rotating seven gun turrets?
Post by: RAAArtyGunner on December 23, 2016, 11:46:56 PM
Interesting topic and some good suggestions/solutions.

Talking Gunnery, don't dismiss the "broadside" that Bob is trying to achieve,  it would be perfectly logical for all guns to train and fire a broadside.

In that situation all guns would fire "parallel' with say the central gun being the "aiming' gun.
Resultant explosions would overlap if using HE and destroy the "ship". Field/Anti Aircraft artillery do like wise.
If concentrated one misses, they all miss.

Even on land bombarding, a broadside may be required to smother/suppress the target along a frontage.

Also at maximum ranges you would not notice any bearing changes between individual turrets/guns for concentrated engagement if the ship was engaging broadside to the target.

Any Naval Gunners????
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 24, 2016, 07:57:35 AM
I would love to replicate this ships broadside ability as most dreadnaughts of the time could only fire four turrets broadsides as echelon turrets on the far side tended to create damage if fired across the deck.

Although Agincourt’s superfiring guns could not simultaneously fire within 30 degrees of the centreline due to the rangefinders mounted on the turret hoods, full broadsides were possible.  Without a Dreyer fire-control table the seven turrets probably trained independently, aided by commands from the foretop control centre.

The rate of fire of these guns was 1.5 rounds per minute.  When a full broadside was fired, "the resulting sheet of flame was big enough to create the impression that a battle cruiser had blown up; it was awe inspiring”.   No damage was done to the ship when firing full broadsides, despite the common idea that doing so would break the ship in half, but much of the ship's tableware and glassware did shatter when Agincourt fired her first broadside.

At Jutland she fired 144 twelve inch shells, although it is not known if any hits were made. 
Title: Re: Rotating seven gun turrets?
Post by: malcolmfrary on December 24, 2016, 09:27:17 AM
Small sailwinches are currently available at not much more than a standard servo.  As much or little angular travel as needed.  A 2-turn winch with its standard 1" drum gives about 7" of linear travel.  Use a continuous loop (easy, the winches come with a double drum)large pulleys to gear down at the turret, hook the line onto a notch as was done on old radio dials to ensure that everything stays in sync.  Excess travel can also be sorted with a servomorh or EPA on the transmitter or both or just be disciplined.  Probably one winch per half of ship and a simple Y lead.  Since the winches are slower than servos, the speed issue  and is taken care of.
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 24, 2016, 10:30:06 AM
 Getting the turrets to train on a ship like Agincourt is certainly worth the effort. From what has been said above it does look like there are two options. Firstly, and relatively(!) simply, is to use an electro mechanical system to move the turrets to train out on either beam and return to the centreline. This is still quite complicated given that they are facing in different directions. It is however a practical option.
 
The second option is the computerised or Arduino route which opens up quite exciting and possibly commercial possibilities as it should be able to develop a turret training module which could be used on any warship and need not be specific to Agincourt.
 
I am not familiar with Arduino but I have done plenty of programming in my time and that side of it should be reasonably straightforward. What is required is a separate module for each turret consisting of a control board and servo mechanism. The control board should be capable of being programmed to set the maximum degree of travel in each direction independently as turrets in early dreadnoughts and other vessels may only have limited training on one side. We would refer to these as direction 1 and direction 2 so as to suit turrets initially facing forward and aft respectively.
 
In its simplest form a central processing unit in the model would be sent a command from the TX specifying the bearing of the target relative to the heading of the ship. This would be passed on to the individual turret module together with the required direction which would examine it to see if it falls within the training limitations of that turret for the specified direction. If so then the turret would train round to that bearing. This would in fact reproduce what the director control on the original ships actually did, with the turret crews lining up pointers to match the director layer instructions. A sub routine might also be used so that if the degree of training specified is outside the turret’s programming the turret would still train round as far as it could in that direction.
 
The icing on the cake would be to introduce a top level whereby the TX operator would specify an absolute direction or position of the ‘target’. The processing unit in the model would identify this by means of an onboard electronic compass or GPS and compare it with the ship’s heading on a dynamic basis thus modifying the signals sent to the turrets with the effect that as the course of the model changes the turrets continue to ‘lock on’ to the ‘target’ Now that would be really impressive!
 
A system like this could be designed, built and sold in the same way as other electronic component sets and as long as the cost could be kept down I think there would be a pretty good market for it. A lot of the technology is already is use in other fields of modelling and elsewhere.
 
Colin
 
Title: Re: Rotating seven gun turrets?
Post by: g6swj on December 24, 2016, 11:02:42 AM
All that Colin has described is within reach of all of us right now - you just need to want to do it!

A cloned Arduino costs less than a tenner

The concept of Arduino is making technology accessible to all - it brings an amazing, powerful and SIMPLE solution to your desktop.

If you can type basic text, connect a USB cable to a computer then you are ready to use an Arduino.

If you have a few minutes then watch this video - it might dispel some of the myth about how complicated it isn't!! - most programs are only a few lines long

https://youtu.be/d8_xXNcGYgo?list=PLGs0VKk2DiYx6CMdOQR_hmJ2NbB4mZQn- (https://youtu.be/d8_xXNcGYgo?list=PLGs0VKk2DiYx6CMdOQR_hmJ2NbB4mZQn-)
 or

http://rchub.co.uk/thinking-about-getting-an-arduino-watch-this/ (http://rchub.co.uk/thinking-about-getting-an-arduino-watch-this/)

or perhaps hit Youtube  and search Arduino or Google Arduino - you will see how BIG this little board has become.

As with most things these days there are thousands of people on forums willing to help you when you get stuck.

Want some more inspiration then browse www.rchub.co.uk (http://www.rchub.co.uk) - a growing resource of web based Arduino and Radio Control articles, ideas, examples etc

You will be amazed at how your creativity is awakened when you understand the basics  - it will certainly stimulate your grey matter!

Have fun and Happy Christmas

Jonathan

Quote
Here is an example program that blinks an LED

void setup() {
  // initialize digital pin 13 as an output.
  pinMode(13, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(13, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);              // wait for a second
  digitalWrite(13, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);              // wait for a second
}

Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 24, 2016, 11:38:23 AM
Jonathon...I do not dispute the valued comments in the technology you offer here ....however this scale Capital Warship would be steaming at some 30+ scale knots when she aimed her broadside at the Enemy

Unless this scale scenario is going to be conducted in a real river or stream some I km long :-) the players here are kidding themselves playing in a 25 m long swimming pool  {-)

Again I suggest we are not conducting an orchestrated ballet movement of Naval Ordinance   <*<

Derek

Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on December 24, 2016, 11:54:33 AM
 
This is going to be a very interesting topic!  O0

Thinking ahead, 'most' servo are quite 'noisy'!
 Anyone know of any 'quiet' servos?

NB:
http://www.modelboatmayhem.co.uk/forum/index.php/topic,35343.msg352119.html#msg352119

http://www.modelboatmayhem.co.uk/forum/index.php/topic,35245.0.html

http://www.modelboatmayhem.co.uk/forum/index.php/topic,37445.0.html

 
Title: Re: Rotating seven gun turrets?
Post by: roycv on December 24, 2016, 11:58:24 AM
Hi, a simple solution might be to buy 10 off 9gram servos (£10 for 10 servos inc p&p, ex China).  Use one to drive each turret, connect them all up in parallel so they have just one lead to go into the receiver. Then  choose a channel that can position the turrets (rotating knob or lever) and leave them in desired position.
Should work and you have 3 servos left over.
I am working on a similar system for operating my points on a model railway layout.
Sorry Bluebird a bit the same as your offering I did not realize this was the second page of the thread!
regards Roy
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 24, 2016, 12:08:09 PM
Roy, the problem with that is that all the turrets will move by the same amount so with the layout on Agincourt, except at the full abeam positions, they would be pointing all over the place!

Colin
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 24, 2016, 12:28:35 PM
hi all

I have been racking my brain, seeing if there is an alternative method to rotate these turrets using electric motors and micro switches - or - using a modified servo tester to rotate servos,. 

To be honest after watching the videos that were posted earlier on regarding Arduino technology is looking the best.   I dare not ask for another Christmas pressie :-) as I have several modelling bits from Mr Claus and when my credit is clear I am going to invest in a starter kit for the Arduino .. to help others understand the problem here is a picture of the layout of the main turrets of the ship.

The other thing I have noticed - this is a Tyne built ship, that was to be sold to foreign powers.
john
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 24, 2016, 12:55:39 PM
John, yes, that is the conclusion I have come to as well. People naturally focus on the electro mechanicals of making a turret rotate but the real problem here is synchronising the movements of seven turrets, four of which start off facing in different directions to the other three, so that they consistently bear in the same direction relative to the heading of the ship.

On the real ship each turret had its own 'brain' in the shape of the  turret crew so you can argue that it makes logical sense to reproduce this now that the technology is readily available and cheap. We need to move away from the gears, elastic bands and cord based approach which would require a Heath Robinson type solution to what is in reality a far simpler method but which requires us to take on board a new skill but a lot of modern electronics is effectively plug and play so it's not really as bad as it initially seems.

I do think there is a commercial opportunity here though for someone willing to seize it using off the shelf components. After all, who makes their own speed controller these days when you can just buy them for £20 and plug them in?

I don't build warships but if I did and there was something on the market at say £15 per turret plus a controller I would certainly be tempted.

Colin
Title: Re: Rotating seven gun turrets?
Post by: g6swj on December 24, 2016, 12:59:20 PM
I would probably go for stepper motors but servos would be ok

Whether moving servos all in synch, at different speeds or whatever combination you fancy - it is easily achieved with an Arduino

https://www.youtube.com/watch?v=-B-jwBnsQPI (https://www.youtube.com/watch?v=-B-jwBnsQPI)

Servo movement for <£10 total plus cable it couldn't be simpler

Full explanation and working code http://www.lamja.com/?p=504 (http://www.lamja.com/?p=504)
*Note - this is a complex solution due to the accuracy involved with timing and the way it's achieved

Regards
Jonathan
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 24, 2016, 01:51:35 PM
There is a wealth of ideas here.  Basics are that this is a ship of two halves so having a receiver in each half, operating from the same transmitter channel, makes practical sense.  Cutting the number of servos per Rx and eliminating inter-hull wiring.  Servo "stretchers" usually appear to work up to 160 degrees. I need 180.  So I am leaning towards a simple 2:1 gear set for each turret rather than drums and string. 

Timing is the next question.  I want them to turn realistically slowly, and not all at the same speed. A P96 operating two random turrets each would do that, and as I only need about 5 seconds hopefully will not judder appreciably. Set each P96 to a slightly different time and depending which turrets they operate could give the desired visual effect. 

The computer solution could be the most elegant but having watched the various video quoted I would avoid that unless I could get it ready programed and servo-connected.  Would that be one Arduino per turret, or one for each half of the model?

Title: Re: Rotating seven gun turrets?
Post by: g6swj on December 24, 2016, 02:16:51 PM
Bob,

I am willing to work with you to get a "pre-programmed" solution if you are happy to make a donation to the RNLI.

All you need to do is specify exactly what you want and I confirm it's deliverable and the cost (components).

One Arduino could do all the servos, slow them down, trigger the independant movement etc.

The only question would be what complications/solutions are involved with a boat of 2 halves!

Regards
Jonathan
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 24, 2016, 02:27:03 PM
hi ya Bob/Jonathan

Looking at the drawings I posted of the ship; wondering would it be possible to split the hull just after the 5th turret in the centre?  that is counting the turrets number 1 at the stern and number 7 would be at the bow?

This would mean that we have 5 turrets in the stern section of the model and doing it this way the majority of the cables for the servos/motors driving the turrets would be all kept together in one half of the hull.   We would only have to have a multi plug for the 2 turrets in the bow section - less wiring and things to worry about.    Just a thought.

Don't forget though, when we split the hull we also have side armament to take into consideration - i.e. obviously you cant split the hull through the middle of a gun housing.

John
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 24, 2016, 03:47:53 PM
Well, it has piqued my interest to the point that I have downloaded John Boxall's book to my Kindle for a bit of Christmas reading. Might invest in a starter set after that.

Colin
Title: Re: Rotating seven gun turrets?
Post by: malcolmfrary on December 24, 2016, 04:12:52 PM
While it is very possible that turrets on large capital ships could be trained over 90 degrees from the centerline, were they?  I read somewhere that letting big guns off at anything other than a full 90 was liable to damage the ship doing the firing more than the target due to the blast from the muzzles.  If that is the case, then 90 degrees each side is enough and it then needs some thought regarding elevation.
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 24, 2016, 04:31:22 PM
On the early dreadnoughts the wing turrets could fire within about 10 degrees of the dead ahead position. Anything else outboard was generally OK although some blast damage was to be expected. The exceptions were axial superfiring which could not be carried out until the turret sighting hoods were located at the rear of the turrets (0riginally the front) and cross deck firing by wing turrets which did cause blast damage and strained the hull so would not normally be done unless the turret on the opposite side had been knocked out.

Any firing where the muzzles were over the deck was likely to result in damage to the deck and its supports and HMS Rodney sustained a lot of damage in this fashion when engaging Bismarck. The later American battleships had floatplanes mounted on stern catapults and these did not usually last long unless they had already been jettisoned!

Colin
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 24, 2016, 04:52:58 PM
okay then; the last 2 areas which we haven't explored are micro pneumatics and also hydraulics.   I have noticed after a web search a lot of these systems are used in robotics and also artificial limbs and so forth.  We all know they can be very precise and smooth in movement.  The only downside I can see at the moment may be the air supply.  The storage tank would have to have a pump to replenish the air supply.  This would obviously be a drain on the main batteries or whatever.   Going the other way and using hydraulics; the down side there would be the connections between the two halves of the hull. because every time you break the hull and reconnect it, you would possibly re-introduce some air into the hydraulic system.

Another bit of food for thought.

John
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 24, 2016, 05:15:13 PM
Interesting point John. The original ships had hydraulic engines for training and usually elevation. The battlecruiser Invincible was originally fitted with two different electrically powered turrets as an experiment but these proved to be unsuccessful and no improvement over the standard hydraulic power which was smoother. Maybe the same would apply to models as well.

Colin
Title: Re: Rotating seven gun turrets?
Post by: unbuiltnautilus on December 24, 2016, 06:57:41 PM
To follow through with the KISS principle, duplicate whatever system of control is used in the fore and aft sections. Two Arduinos or two hydraulic systems or two banks of servos. Too many through hull connections could be prone to failure due to water splashing while separating the hulls at the end of a run, not an unknown situation. Also, half a ship would fit easier on a work bench. If it is self contained electrically, it will be easier to set up, not requiring the other half of the ship to be connected for any electrical work.
The aft, radio control section of my 100" SS Ohio is only 26" long, very manageable. While the forward pyro control unit is actually modular, in a 8"x 6" box, while the entire hull section is only 44" or so long. All easy to work on.
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 24, 2016, 08:45:15 PM
Self contained independent halves is the way to go, for all the reasons you say.
Incidentally I did read right through your interesting SS Ohio build thread to see how you accomplished the actual hull joining.

My intended project must separate at exactly half hull length as even then the halves will be a tight squeeze in my Agila, both parts travelling side by side.  Before anyone suggests it, I had considered WW1 MKI tank sponsons on the rear passenger doors, but that may have upset the M.o.T. testers modifying the vehicle to seven and a half feet wide.
Title: Re: Rotating seven gun turrets?
Post by: cos918 on December 24, 2016, 09:19:41 PM
Hi Bob
you have been many good ides . Have a look at this radio . it comes as 16ch but can be expanded to 32ch . You could easily assign single or banks of guns to a ch


john
https://www.frsky-rc.com/product/pro.php?pro_id=143


 
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 24, 2016, 10:42:21 PM
As Colin notes with 'hydraulic drive', this essentially was an electro hydraulic mechanical drive…..the original vessel turret motion was provided by a DC electric motor driving a hydraulic pump which drove a hydraulic motor connected to a high ratio helical speed reducer which for elevation rotated  an outboard precision worm which was directly connected to a large elevation worm wheel arc. The train motion was of similar design. One point to understand here is that the electro hydraulic mechanical drive system were designed and controlled with an accuracy to point the barrels at degrees and minutes of position

Sub miniature [1/12 scale] true hydraulic pumps/valving/linear actuators and geared motors are available and used exclusively in RC off road equipment, however having spent a lifetime in mercantile marine, industrial and Naval hydraulic systems, I would suggest these components are grossly out of practical scale for a 1/96 scale vessel

The same would apply to any fluid pneumatic system which would rely on an air accumulator. Miniature fluidics [pneumatic] valving is available, however converting this to rotary or linear movement is problematical

The every kind offer from Jonathon to assist with the basic design going down the Arduino path and would be worthy of consideration, however as he states.....a full set of parameters would be required.....this must include the intended scale waterway and speeds and turning circle for the vessel. An advantage here would be the facility to input pointing and non pointing zones or firing and non firing zones

[Courtesy of Wikki]…..[It is often stated that the seven turrets were named after days of the week rather than the letters usually used in the Royal Navy.[10] They may have been known by crew members by such a designation, but in official literature the turrets were numbered 1 to 7.[11] John Roberts has informed the editors that the as-fitted plans of Agincourt from 1918 reflect this usage.[12]

[Reading this surprised me as I had assumed the nomination would have been A, B to X &Y etc] So No 1 turret is foremost at the bow, then working back numerically to the stern

No 1 & No 2  turret would have a full say 80 degrees +/- to port & stdb pointing and firing zones, No 3 turret ...would  have the same extreme 80 degrees +/- to port & stdb pointing & firing zones, however at approaching say +40 degrees to axis would enter a non pointing zone - non firing zone until  -40 degrees was reached

To better understand, a non pointing zone is one in which the system will not allow the mount to make a physical stop/end of movement with the barrel pointing in this zone. Naturally mounts  No3 & No 4 etc will need to be traverse or be driven through the arcs on non pointing zones, however the mechanical computers in these mounts precluded the mount to stop, or fire

May well be worth going back over a long Battleship thread here on MBM from Geoff in his trials and final gun mount systems he installed,

As you go down the path of controlling the speed of the turrets will open Pandoas box, in that true scale speed of turret movement will to the human eye and mind not be appropriate……yes certain non scale movements will be needed

Still a very interesting subject........Derek

Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 24, 2016, 10:50:59 PM
"this must include the intended scale waterway and speeds and turning circle for the vessel."

I'm not quite sure what you are getting at here Derek - could you explain a bit more?

Colin
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 24, 2016, 11:17:48 PM
Merry morning Christmas wishes Colin O0......

This  question......the really depends on how much scale Bob wishes to be created......battleships of this era did not fire broadsides at close quarters and still speeds of Nelson or Drake as such, however these Dreadnaught Class vessels would fire at a vessel on a converging or intersecting target point of some considerable distance and not two vessels steaming in opposite directions

If Bob intends to use his 2m long vessel in a 20m long x 5m wide home pool, the vessel at a pre determined part angular broadside would need to be made at an imaginary target 200m away. The amount of concentration to the train positioning of the individual 7 turrets would probably need the vessel to be near stationary in that 20m pool

From experience, a 2m long scale vessel would need some 3 x 3 point turns to reverse direction in that 20m long x 5m wide home pool

Derek
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 24, 2016, 11:45:02 PM
Still waiting for Santa here..... ok2


I see what you mean as far as Bob is concerned. However I was rather looking at things on the basis of the model swanning around on a biggish pond/lake in the usual way with the skipper demonstrating that the turrets could train and elevate and also maintain a bearing on the hypothetical target irrespective of what course the model is steering. The full size equivalent might be the behaviour of Warspite at Jutland when her steering jammed. Although the ship was hoing round in circles the msin armament was still aiming and firing at the enemy line.


Bedtime now!


Colinm
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 25, 2016, 08:07:08 AM
Whilst I am an Arduino advocate you might want to put this on the late Santa request list - Maestro Servo Controller available in 6,12,18 and 24 channel versions (£20 for 6ch - £35 for 24 ch)

Programmable via your computer with on screen easy to use interface it creates a sequence of instructions in the form of a script that can be saved and run from the board stand alone when not connected to the computer.

https://www.pololu.com/product/1352 (https://www.pololu.com/product/1352)

Regards
C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 25, 2016, 08:35:11 AM
Morning all.  Merry Christmas  O0
Just slipped into the workshop for a puff, and put the computer on.

Thank you all for the super suggestions and technical information.
Normal Home Waters for me is Black Park Lake which is around 250 meters wide, and much longer though we don't use the 'Island' end.  So plenty of room.  However much more than 10 M from the side any on-board movements become less visible.  Agincourt was not known for her turning circle so I will do my usual and make the rudder a lot larger, aided by proportional control of the outer props.  With a model perceived movement and speed is rarely true scale anyway, but what 'looks' right.  She will also be used on waters such as Wicksteed where an enhanced turning circle is essential.
Guns will train on an imaginary target, not a scale 20,000 yards (almost full lake width).  I will need to train a full 90 degrees at least for a full broadside.  My aim is for a reasonable perceived turret movement, slowed rotation, not all exactly together in a modern Ballet synchronisation.

Any Adruino solution I would need some serious assistance on, as I said before.  Otherwise I will go for geared drives and maybe three servo slowers to have slightly different visible rotation speeds.
Title: Re: Rotating seven gun turrets?
Post by: kinmel on December 25, 2016, 03:02:34 PM
Arduino, or Raspberry Pi will control up to 12 servos (and/or esc ) either individually, or in groups, using one of these ......    http://www.hobbytronics.co.uk/raspberry-pi/servo-pro-12ch. 

Full setup details on the page.
Title: Re: Rotating seven gun turrets?
Post by: g6swj on December 25, 2016, 08:41:48 PM
Bob,

Lots of great info and suggestions here!

Can I suggest for now that you forget any technical solutions and simply specify what functionality you would like to have assuming that technology can support your wish list.

Some things you may want to think of to start to create your shopping list/functionality specification:

Some of this scale functionality may not replicate what happens/happened on the real ship(s) - but this is your list so as far as I am concerned there are no rights and wrongs!
Once you have your "dream" list of functionality it will perhaps help determine which technology route can best deliver a solution.
I do understand that the KISS servo morph route may be attractive - however if you are up for it with help you have the opportunity to chart some new waters!
Regards
Jonathan
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 25, 2016, 08:51:32 PM
If you are busy steering the model around the pond then the less you have to do to micromanage the main armament the better! I would think it is best to emulate full size practice if possible. The captain cons the ship, the gunnery officer endeavours to keep as much of the main armament pointing at the designated target as possible. Don't try and simulate local turret control - that way madness lies... :o

Colin
Title: Re: Rotating seven gun turrets?
Post by: kinmel on December 25, 2016, 09:26:36 PM
If you are busy steering the model around the pond then the less you have to do to micromanage the main armament the better! I would think it is best to emulate full size practice if possible. The captain cons the ship, the gunnery officer endeavours to keep as much of the main armament pointing at the designated target as possible. Don't try and simulate local turret control - that way madness lies... :o

Colin

If you go the microprocessor route you can designate the target bearing and then guns can keep their bearing to the target as the ship turns.  You just need to invest the time needed to meet your wishes.
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 25, 2016, 09:41:12 PM
Exactly, that is what I said in my earlier post.

Colin
Title: Re: Rotating seven gun turrets?
Post by: g6swj on December 25, 2016, 09:55:25 PM
If you are busy steering the model around the pond then the less you have to do to micromanage the main armament the better! I would think it is best to emulate full size practice if possible. The captain cons the ship, the gunnery officer endeavours to keep as much of the main armament pointing at the designated target as possible. Don't try and simulate local turret control - that way madness lies... :o

Colin
Hmmm - this may well be the case but it does pre-judge the effectiveness of the interface between the human and the control system  - for example this interface could be voice commands which mean you do not need to take your eyes off the vessel, I can think of other options which could work effectively.

My intention was not to limit the shopping/ functionlity wish list, clearly aspects of the functionality may be discarded as impractical, impossible to support with technology or just plain over the top etc. There is nothing worse than - "I was going to mention but ...."

One aspect to consider maybe "Exhibition mode" - that delivers specific functionality/movement of turrets when model static on show....

If this type of solution is to exist there needs to be a "blueprint" to work from which was the main reason for my post.

Regards
Jonathan
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 25, 2016, 10:13:31 PM
Yes you are quite right Jonathan, before you start you do need to have a clear specification of the functionality you wish to achieve and how you intend to use it. The absence of this is the main reason why so many computer based systems ultimately fail. That and the inability of the commissioning agency to refrain from constantly changing the spec as the project proceeds. The other common failing that the armed forces seem to fall into is over specifying so that what they want is not necessarily what they actually need which might be rather simpler. TBH I cannot think why you might want to have different control inputs for individual turrets unless you intend to engage more than one target simultaneously which would have been very unusual, even in WW2.

In this case I think that the overview objective, as stated above, is for the main armament to follow the target irrespective of the changing heading of the ship which is what I tried to briefly specify in one of my earlier posts.

Having worked out the basics of how that might be done then it is possible to look at refinements such as being able to provide for adjusting the rate of training of the turrets so that it looks right and to interface with a a servo or motor that gives a smooth rather than jerky movement. As you say, at the TX end, the operator might have alternatives by which the desired target bearing could be input. A verbal command based on the number of degrees away from true North for example.

As will be seen from this topic, there is a natural tendency to focus on detail before looking at the overall requirement and identifying potential problem areas which in the case of Agincourt include the geometry issues associated with the various turrets starting out in different alignments from rest. This really does complicate any electro mechanical solution but should be very simple to solve if each turret has its own control module.

Colin
Title: Re: Rotating seven gun turrets?
Post by: g6swj on December 25, 2016, 10:36:33 PM
Colin,

I note that your interest "piqued" regarding Arduino. I am sure you will find it quite easy to make rapid progress with microprocessors, especially with your previous experience in programming and the logical approach to solutions that brings.

My starter for 10 wish list/suggestion regarding individual/groups of turrets movement may have been a red herring!

The start "home" point of each turret is simply overcome as you infer - you simply have a "home position" value defined for each servo in the program.

If going the servo route (ignoring for the moment a ship of 2 halves) the only control unit would be a single Arduino with servo's plugged into it in a similar fashion to a radio RX.

Regarding "jerkiness" of servo movement this is definatley an issue with Arduino PWM signals - the jitter can be quite a problem. There are work arounds/solutions but the programming can become pretty scary and like most things also has some consequences. However with simple and additional cheap hardware ( one option Kinmel has detailed) there are solutions to this which in themselves bring multiple benefits.

Slowing the servo movement & soft start/stop is easily achieved.

One thing I wondered about - what would happen when the ship turns at the end of a boating lake? - would the guns simply need to track to the opposite side of the boat?

There is also a risk of taking this all to seriously - the fun aspect can't be lost!!

I have escaped Chrimbo TV - duty beckons - I just hope Strictly and Bake Off have been and gone!

Regards
Jonathan
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 25, 2016, 11:15:51 PM
Jonathan,

I have been speed scanning the Arduino book and while I have not absorbed the detail, I can follow most of the logic. The programming itself looks relatively straightforward although the syntax is different to what I was used to (I wrote a commitment accounting and property management system in Foxpro). The interfacing with the external inputs and outputs is something new as I only had to worry about keyboards, screens and printers!

Can I pick up on two points in your last post?

Firstly you say that one Arduino board could control the seven servos needed to operate the turrets but how do you allow for the fact that in order to zero in on a selected bearing, four turrets would need to turn in one direction and the other three in the opposite one? One set of turrets might only have to say, move 30 degrees to bear on the target but the others would need to turn the reciprocal which would be a much greater movement. In fact several of the turrets would need to turn by different amounts to line up together. This is why I assumed that each turret would need its own decoding unit to compare where it was with where it needed to be.

Secondly, re your point about what happens when the model gets to the end of the lake. This is essentially the same as what happened when Beatty's forces ran into the High Seas Fleet at Jutland. Initially all the turrets were bearing to port but Beatty had to make a 180 degree turn so as the ships turned round all the turrets had to swing back through the centreline and bear on the opposite beam.

I can't see any real need to dynamically control the speed of the turret rotation, in reality they would all be around the same as makes no difference but I can see that it would be necessary to set a default speed to be able to fine tune what looks 'right' on the model. Presumably a variable can take care of that if controlled by the Arduino board.

With regard to the jitter you describe, assuming that the actual servo is capable of smooth movement, as most are, then would it be possible to deal with the speed adjustment mechanically, using gears to achieve the desired rate of turn with full voltage applied to the servo. Then, could the Arduino board simply apply full power to the servo until it reached the stipulated bearing? This would obviously entail a 'hard stop' but if the turrets are turning relatively slowly anyway it might be OK. Or, if as you say soft starts and stops can be accommodated, then could the board apply full power to the servo until within perhaps 5 degrees of the required bearing and then go into soft stop mode? I think it would be something of a suck it and see situation for which a test turret mechanism would need to be constructed.

We learn something new every day!

Colin
Title: Re: Rotating seven gun turrets?
Post by: g6swj on December 26, 2016, 12:00:52 AM
Colin,

The Arduino Uno has several PWM ( Pulse Width Modulation - a square wave signal) pin connections.  Hardware wise it has only 6 PWM pins - there are ways to use other pins as PWM connections.

Each PWM pin can be set to a specific value (ms) - and therefore set the rotation/position of individual servos. You may well need to have an "offset" for each individual servo to make them equal to their colleagues - tracking wise you would be able to get them to all head in the same direction (may need some clever adjusting)

The jitter is caused by a slight timing difference( due to interrupts in the Arduino chip) in the PWM square wave signal that causes the servo to move very small amounts as it's PWM varies minutely.

I think there maybe some confusion regarding how the servo works - it has nothing to do with the voltage changing - it is due to the width of the pulse (PWM) - typically 1.5ms square wave being the centre position of the servo - 1ms and 2ms the full travel PWM's

see this link http://www.seattlerobotics.org/guide/servos.html (http://www.seattlerobotics.org/guide/servos.html) or https://www.youtube.com/watch?v=EpB53YZc3rs (https://www.youtube.com/watch?v=EpB53YZc3rs)

I could not agree more with the learning comment - one of the reasons I play with Arduino's and the like is to keep my mind active...

Regards
Jonathan
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 26, 2016, 01:01:14 AM
As much as I admire everyone's technical enthusiasm here, there are some practical limitations in a model on lake scenario.  Before getting into constant GPS bearing issues, our lake is 'only' 250 m wide (around 100 ship lengths ) and well before you get a third of the way across turret positions will be all but invisible from shore.  Rather different to displaying a model tank a few yards away.

The second issue is having two independent halves is a practical must-have. I have a distinct aversion to unplugging connectors, except for maintenance, especially servo leads.  It is asking for reliability problems.  I tend to charge batteries via on-board charging sockets with a C/O switch. 


Elevating the barrels are best effected mechanically by internal ramps and springs.
Gun fire sound / LED's a separate channel, via a Tx switch.

Hopefully the above wish list is not too complicated.

Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 26, 2016, 09:10:05 AM
Some further thoughts, after carefully reading and viewing all the various links provided.
One of the biggest problems in my mind is when getting the forward facing guns to point, say, 30' to port, the rear facing guns will have to traverse 150' in the opposite direction.  That alone leans towards internal calculation as against say a 5 servo controller which although can set individual turrets to reverse direction is not able to calculate how much by.
A fixed aim point of 90' abeam would avoid this, but be of limited use.

Traversing more than 160' total would risk servo judder, even in computer versions, but although work-arounds exist they appear to complicate programming.  Ideally a 270' servo would make physical movement simpler than gear trains. ie:  have the turret axis mounted direct over the servo axis.

The more I read online the more I am thinking that some form of computerised device is needed in each half.

Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 26, 2016, 09:55:57 AM
Bob,

The calculations bit re a turret moving is simple.

Even for <£10 you are getting an Arduino capable of 16 million clock cycles a second - a few calculations don't even make it break into sweat.

Re the servo jitter - assuming the servo can physically move without jitter to it's end points then a simple additional chip <£5 will eliminate the microprocessor causing any jitter

The 2 halves issue does need some thinking about to make the most useable solution. Clearly if 2 control units involved they will need to receive instructions from you main TX to do their thing!

It would be possible to re-transmit a signal from one half to the other on-board - perhaps via Infrared if a Infrared TX/RX sensor could be placed above deck in line of sight with each other - one in each half- some of the sensors are no bigger than a typical LED - this way only one of the units would need to be directly connect to the RC receiver.

What make and model of transmitter are you thinking of using?

I appreciate that the unknown subject of the microprocessor can be daunting - with help, and as time goes on you will be amazed at how simple it can be

One aspect of this that it worth pointing out is that if you compare pasting text into a Microsoft Word document, amending a character or two and then hitting save - this is no different in concept to programming an Arduino. So if people help you they would send you the program text via email.

1. Text is entered into text editor (Arduino IDE) which could simply be pasted text supplied to you from an email
2. Hit save to save the doc
3. Hit upload - and the program is sent to the Arduino down a USB cable in a few seconds

Job done

C-3PO

Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 26, 2016, 10:01:36 AM
Bob, I was going to apologise for hijacking your topic a bit but you have highlighted an issue which has plagued model warship builders for decades! From what Jonathan has said and from my initial reading of my Arduino book it is evident that the various components and techniques already exist to put together a sophisticated main armament control system. It just needs someone to put in the development work to make it all come together. But in doing so the aim should be to develop a generic module which can then be programmed with the variables needed for the particular application it will be used for such as maximum traverse angles, rotational speed etc. It could then be very simply adapted to any situation, even dreadnoughts with wing turrets.

In your case I don't think that splittting the hull will be an issue. It is possible to bind two RXs to one TX using the 2.4GHz system so both receivers would be getting exactly the same signal from the TX. So each hull half can have its own independent system

In your earlier post you mentioned a rotary control, but, as you have realised, if you simply wire up all the servos together then pointing the forward facing turrets 30 degrees off the starboard bow will simply cause the aft facing ones to point 30 degrees off the port quarter. Reversing the servos for the after facing turrets would just mean that they pointed 30 degrees off the starboard quarter instead. This is why I suggested that in practice a simple electro mechanical system will only give three positions with the guns facing in the correct direction, 90 degrees on each beam and on the centreline. For this you only need a single push button to cycle through the three positions. The turret servos would need to be geared down to an acceptable visual rotational rate and you could vary this slightly for individual turrets by slightly altering the gear ratios. All this would probably work OK eventually but would obviously not be as good as a fully computerised system with all its extra features.

Rock and a hard place perhaps?

The place to start, as always, must be to prepare a generic specification for the developer to work to so perhaps we could try and agree a list of desirable features as a basis for this.

Colin
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 26, 2016, 10:33:35 AM
Bob, I was going to apologise for hijacking your topic a bit . . .

Not in the least Colin.  Your detailed responses have been most interesting and relevant.

Yes, I use a 2.4GHz Planet system for everything that does not submerge or semi-submerge.
Maybe a system that has a number of channels for forward facing guns, plus channels for rear facing guns, could become a generic for a wide variety or turret warships.  Two units, programed identically, could thus be used in either half of the hull.  With suitable calculations matched bearings totalling 270' per turret should be possible.

I had put my wish list in an earlier post.  Anything beyond this a bonus.
This is a silly sized build, but at least internal space is no object  {-)

Thanks again.   Bob K
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 26, 2016, 10:34:13 AM
Bob, Colin,

This may shed some light on the simplicity (Arduino PWM & Servos)

https://www.youtube.com/watch?v=GzTPa0UL6vo (https://www.youtube.com/watch?v=GzTPa0UL6vo)

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 26, 2016, 10:57:59 AM
Bob, if I have grasped the possibilities right then it should be possible to do the whole thing with just one rotary channel on the transmitter!

I will have a shot at a basic spec.

Colin
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 26, 2016, 11:26:06 AM
Bob/Colin,

Unless I am mistaken the Planet TX does not have a rotary proportioanl encoder/Pot ("knob"). - it might be possibel to add one.

It would be possible to use a resistor ladder within the TX on one of the proportional channels to add a bank of buttons to the TX allowing events/functions top be triggered

Eg Button for Stop/All guns to 90 degrees port / all guns to 90 degress starboard / all guns "home" position.

Or you could use one of the proportional stick to do the same

Stick full up long > 1 second - All guns 90 degree port
Stick down long > 1 second - all guns 90 degree startboard
Stick down short <1 second  - xxx
Stick up short < 1 second - yyy

Stick half up short <1 second - all stop

The Arduino on the boat can work out what signal has been sent a then invoke the relevant function

Have fun with the spec....

PS - another great point of this style of development is that there are several people on this forum that know and love (as well as hate) Arduino's

For example Tim "tsenecal" has created  Nautic decoders for Robbe F14/F16 and the like using an Arduino for the cost of <£10 - compare that to the price of the original kit!

Have fun

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 26, 2016, 11:34:54 AM
The planet T7 has a rotary control for channel 6, plus a three position switch for channel 7.
Also a slow-rate or normal-rate retract/flap switch on channel 5.

It would be nice to set an angle for all guns to point to
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 26, 2016, 11:48:09 AM
I will throw the draft spec below into the ring for comment, hopefully it should show up any inherent problems. The operator does need to know roughly where the cardinal points of the compass are from where they are standing but that shouldn't be a problem. North should line up with the mid travel point of the rotary switch.

Colin

 Model Warship Turret Control Basic Specification
 
Objective:
To enable the turrets on a model warship to dynamically bear on an absolute target bearing remotely specified and constantly changeable by the model operator.
 
TX Input
The operator should be able to specify and alter an absolute target bearing expressed in degrees from true north using a rotary control on the TX
 
Model Onboard Components
GPS or Electronic Compass capable of determining and outputting the number of degrees by which the model’s heading deviates from true north.
 
Control board capable of comparing the heading of the vessel with the specified target bearing from the TX and outputting the difference as degrees based on 0 degrees being the bow of the model  and 180 degrees the stern. (0 - 359 degrees range)
 
A servo module for each turret which is pre programmed with the allowable maximum traverse in degrees each side of the centreline of the model and also the desired rotational speed of the individual turret.
 
Means of Operation
The operator specifies the absolute target bearing in terms of compass degrees and transmits it to the model.
 
The model compares the transmitted bearing with the model’s actual heading dynamically and transmits the difference to each turret module which informs the turret module of the bearing of the target relative to the current axis (heading) of the model.
 
Each turret module examines the relative bearing to the target and checks to see if it is within the pre programmed traverse limits for that turret. If so then the turret will traverse until it matches the received bearing and will continue to follow it while it is within the turret’s limits of traverse. This might entail moving in either direction depending upon how the model is changing course. For example a turret may need to swing right round to the opposite beam to stay on target. This can all be done in the module programming.
Optional: The turret module may feature programmed soft start/stop for extra realism.
 
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 26, 2016, 06:13:58 PM
hi there Bob are you still with this topic :-)

As I have stated previously the mention of electronics sometimes puts people off and I think this topic might put a few off.  Basically all that is required is to train the guns on an imaginary point on the lake where all the guns point at the same area.  They don't have to be clinically correct to Royal Naval standards and to the degree which I think we are 'aiming' for in this topic.   Having said that though the old grey matter went into remembering mode - because - years ago I built an electrical circuit called a Servodriver.

It is based on an IC chip numbered IC741 - way out of date now - but the principle was to mimic the pre-set range dial which was independent - originally built for a remote controlled radio aerial.   I could preset/move the aerial around to obtain different signals.   Bearing in mind the aerial was mounted on the house roof (I was using this for listening to amateur radio).

My thinking is under say, the main one turret, which is going to become the main turret, you have the main select pot of variable resistance and also this main drive gun was driven by a servo as well which was controlled by the handset.  Basically it is the same as I had suggested earlier on, but, instead of using servos you use geared motors on the rest of the turrets which would mimic the movement on your first turrets.

Maybe a simpler system to construct and understand.

Last but not least, could you not keep the hull as one and fit a roof rack to your car?  You could then place the hull on the roof rack and make the whole deck / superstructure to split into two and fit inside the car?

John
Title: Re: Rotating seven gun turrets?
Post by: unbuiltnautilus on December 26, 2016, 06:48:52 PM
Almost all of our 8 foot plus models are now built to at least split in half. Our 6 foot battleships are currently two built in one piece and two split in half. We still have one 102" battleship in one piece. It is a two man job to put it on the roof. It makes life easier generally if you can divide the model up, for both transport and storage.
The only disadvantage we came across was this, more trips to get the model in the car, and more trips from the car to the lake! Build a trolley to take everything in one move.
I like the idea of the master ( A ) turret, controlling everything else, however, I am now most interested in the electronic solution. Some of the suggestions are possibly straying into realms of sophistication not needed on a model boat. However with a little additional technology, and a couple more models with similar electronic fits, a proper sea battle could be staged. Including IR firing, registering hits etc..let us walk before we can run first.
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 26, 2016, 06:58:49 PM
I think you have glossed over a bit there John! The first turret could be used to control turrets 2,3 & 5 but how would you construct a linkage to turrets 4,6 & 7 which start off facing in the opposite direction and would need to rotate by an entirely different amount for any given required bearing?

Colin
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 26, 2016, 07:42:35 PM
There is another restriction to roof racks.  A height bar over the entrance to our lake car park.  I have seen it remove bicycles most dramatically.  Definitely a two man lift involved, then getting it to the water.  Halves are easier to manage.

A little side step here.  I hope we are not being carried away with having seven turrets.  Try thinking of four turrets on a WW2 destroyer, facing both fore and aft.  Even HMS Devastation with just two.  Crack Devastation and you have solved the problem, as after that it is just more of the same.  I have seen it done so there must be existing solutions.
I have seen examples at Wicksteed.  The Portsmouth Display team run gun battles with turning turrets.  Whether this is done with a single control I have no idea though.

Title: Re: Rotating seven gun turrets?
Post by: NFMike on December 26, 2016, 09:27:09 PM
The principle required is fairly simple.
Each turret is equipped so it knows where it is pointed relative to dead ahead and arcs where it cannot point.
A central control knows the ship's compass heading and is told the compass direction of the target. With a bit of math it works out the target bearing relative to the ship's head and sends it to all the turrets (and updates this whenever the ship's compass heading or target direction changes, or just continuously).
Each turret then rotates to the target bearing (or as near as it can) and decides whether it can fire at the target (not if it can't reach the bearing or is in a no-fire arc).

In the case of a micro-computer the turrets will largely be virtual objects within the program, with just the servos at the turret (assuming use of servos).
Achieving that isn't so simple of course.
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 26, 2016, 09:55:48 PM
Bob........don't  let the turret numbers 1 to 7 inclusive put you off :o.......

Our MBM member Geoff with his 1914 Iron Duke has mastered getting turrets A, B, Q, X & Y to point at the same target.....[and fire].......brilliantly achieved :-))

http://www.modelboatmayhem.co.uk/forum/index.php/topic,43803.msg587567.html#msg587567

Derek
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 26, 2016, 11:34:50 PM
Derek, that photo you have posted shows that the forward turrets are firing on the port bow while the aft turrets are actually pointing over the port quarter. The other photos posted on Geoff's topic appear to show that the turrets only all bear in the same direction when firing at 90 degrees on the beam. Correct me if I am wrong but this would appear to be basically the 3 position electro mechanical system referred to earlier as opposed to the ability to point all the turrets in the same direction when the target is between 0 and 90 degrees from the ship's axis as would be feasible using an Arduino solution.

Plague has essentially repeated my draft spec for this in his post.

Colin
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 27, 2016, 08:29:43 AM
Geoff's Iron Duke is a masterpiece IMO.  I loved following his simulated gunfire thread.   :-))

A little lateral thinking on turret positioning.  How about if all guns could theoretically train the 360' specified by required bearing commands, but had microswitches to cut power to the servo when it attempted to enter the no-go zones of obstructing superstructure ?  Thus each turret starts at 0' (bow) and can only turn when the bearing value passes beyond its limiting zone angle.  Is an electro-mechanical solution possible ?
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 27, 2016, 09:56:53 AM
 Bob, if you are considering a computerised/electro mechanical hybrid then yes, something could probably be cobbled together but you would be substituting a lot of limit switches and fiddly wiring for maybe half a dozen lines of computer code – not a very good trade off.
 
It has become very apparent from the posts on this topic that while people may be prepared to accept that to achieve an all singing, all dancing turret control facility a computerised solution is necessary, it clearly takes many of them well out of their comfort zones and that is entirely understandable.
 
Our Arduino experts argue that Arduino is simple when you get to grips with it and for them it is. But any form of programming does require a new skill set and it is not one which is a natural extension from our normal modelling activities. Moreover, computer programming does require very precise and logical thinking and the ability to resolve problems (bugs) in the code as a mental exercise whereas we are more commonly used to looking at something visually on the workbench. Some people are better than this than others who may really struggle to make sense of it all.
 
This is why I suggested that there is a commercial opportunity for anyone able and willing to develop a generic prototype. OK, it might just be pin money but I think there would be a reasonable demand.
 
It doesn’t make sense to me to have a lot of people attempting to develop their own solutions. A generic system can be applied to any naval vessel from a single turret monitor to the seven turrets of Agincourt – it really is a one solution fits all situation.

So you could just buy the central control board with its GPS/electronic compass shield pre programmed and then one sub module for each turret (and maybe the gun director too!). The turret modules could come pre programmed to bear up to 90 degrees from the ship’s keel line and work straight out of the box but could also be individually programmed from a user friendly program on your computer which allows you to tweak the permitted bearing angles and traversing speeds.

A TX with a rotary control would be needed otherwise the R/C would be standard gear.

So, is anyone willing to take the plunge and have a go at doing this? If it is as easy as our Arduino experts tell us then it is just a question of their time plus the cost of the individual Arduino components needed to make one turret work.
 
Colin
 
Title: Re: Rotating seven gun turrets?
Post by: malcolmfrary on December 27, 2016, 10:13:58 AM
Colin put his thumb spot on the main problem in an earlier post.  You do need to know what you want your system to do before you start designing it.  I always found that writing down what I wanted my program to do in plain English was a good start in writing the actual program in terms that the processor would understand.  If I couldn't make solid logic from the English version, I would have little chance in computer language.
Computers of any type do do exactly what they have been told to do.  This can be embarrassing.
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 27, 2016, 10:54:00 AM
Hey guys, I accept the principles of what you are saying, but after researching all the links given I can't see where to even begin.  I have done PC programming before, mainly BASIC, Fortran & Assembler, but even 'simple' tasks like noughts and crosses can take a huge amount of time to get working.  I have already listed out my desired parameters of operation, to which I will add one more.  For any realistic operation you have to train turrets up to 135 degrees each side otherwise it will merely look like two separate manual control systems for fore and aft facing guns.  There will be a huge number of embedded conditional loops with slowing, stop and start somewhere in the centre.

ie:
Get GPS value
Get desired bearing value
Calculate relative angle
Can this gun achieve this relative angle, if so initiate start loop.
   Is relative bearing at least 6' for start plus stop loops?
         Run slow training.
               check relative bearing difference is still within current range
                    if bearing difference is within, say 3' of optimum start slow down loop
               check relative bearing difference is still within current range
         Run slow training.
Check firing bearing has been achieved
If yes go to get GPS bearing.

Something like this?  I particularly like the Arduino's with triple pins that you can plug servo leads straight into, otherwise a rats nest of wiring will be necessary.  Arduino compatible GPS units can be bought for under £13.
My ideal would be two identical units, each with half the channels (0-4) forward facing turret capable, the others (5-9) for rear facing turrets.  That way you can plug in servo leads according to turret orientation.
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 27, 2016, 11:38:24 AM
So, is anyone willing to take the plunge and have a go at doing this? If it is as easy as our Arduino experts tell us then it is just a question of their time plus the cost of the individual Arduino components needed to make one turret work.


Colin, this is my plan for January!


I'll be using an Arduino Mega, a solid-state compass (don't need GPS) and a clatter of geared stepper motors. Plus lots of wire. I've already soldered up a controller for testing, which will replicate a TX. It's got a rotary pot (for bearing info) and two switches ('on', 'off', 'park'and 'track'). A dozen LEDs for turret status and feedback. Total cost is about eighty quid.


I'll set up a thread when I start programming.  :-))


Andy



Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 27, 2016, 02:58:46 PM
Wow Andy, that sounds awesome,  I am sure this could be a highly popular solution as almost everyone with a turreted warship could benefit by adding realistic gun orientation.  I would be happy to contribute to development costs, especially as I introduced the problem at the start of this thread.

Reading up on stepper motors vs servo's I can see there are some technical advantages, but to maximise take up I suggest basing it on servos as modellers with existing warships could also buy into this to optimise maximum potential.  Also, any means to minimise wiring would greatly boost usage.  ie: Being able to plug servo connectors straight into the Arduino. 

I aim to pick up the hull in the Spring, fitting the running gear and bulkheads first, so absolutely no hurry.
Anything I can do to assist, just ask. 
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 27, 2016, 03:21:55 PM
Sounds great Andy, I think a lot of us will be following your progress with interest. Definitely a worthwhile project.

Colin
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 27, 2016, 04:26:15 PM
yes I think we will all be sitting ready - I have me jotter open and pencil sharpened already :-)

John
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 27, 2016, 04:57:33 PM
Reading up on stepper motors vs servo's I can see there are some technical advantages, but to maximise take up I suggest basing it on servos as modellers with existing warships could also buy into this to optimise maximum potential.  Also, any means to minimise wiring would greatly boost usage.  ie: Being able to plug servo connectors straight into the Arduino. 


The thing is, the geared steppers are good to about a twelfth of a degree of angle, don't have servo-like limits, and can be repeatably positioned to the same point for as long as they're powered up. If that's not enough, they cost <£5 off the 'Bay.


 :-))


Andy
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 27, 2016, 05:03:32 PM
- any good suggestions of what starter kit to look at for  Arduino boards?  I have been browsing the web - and there does seem to be an awful lot about.

john
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 27, 2016, 09:21:22 PM
dreadnought72 ......Andy.....when you say...'geared steppers are good to about a twelfth of a degree of angle'....that is certainly greatly exceeding the repeatable train position for this model application.

I have little if any real knowledge of stepper motor characteristics,.....so just as one simple parameter that seems not mentioned to date %), can a geared stepper provide a smooth [jitter free] output shaft movement of say 90 degrees in say 4 seconds?..........

Derek
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 27, 2016, 10:13:12 PM
Yes. I've conducted a few tests with these geared steppers and that speed is achievable. Go too fast, though, and - while the Arduino can pump out the steps quickly enough - the stepper driver chokes on the digits and the motor stalls out.


Andy
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 27, 2016, 10:56:50 PM
John,

Before splurging the cash I would suggest reading up on the subject a bit. I bought the Kindle edition of John Boxall's book:

https://www.amazon.co.uk/Arduino-Workshop-Hands-Introduction-Projects-ebook/dp/B00CLHK0OQ/ref=sr_1_1?s=books&ie=UTF8&qid=1482878772&sr=1-1&keywords=john+boxall

It is very readable and very informative. It will certainly give you some ideas on what you might want to buy to get started.

I rather doubt if I will take it further at the moment as I don't normally build warships and the only working feature on most of my models tends to be lighting so the effort in getting to grips with the Arduino syntax and interfacing isn't directly relevant to my modelling. However I do find the Agincourt subject very interesting but more in terms of defining the specification, outlining the programming requirements and seeing what interfacing options are available to make it all work.

When you think about it, the possibility of being able to exercise proper 'director control' of the main armament on a dreadnought battleship model using just one R/C channel is pretty amazing really!

Colin
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 28, 2016, 12:05:34 AM
A lot of mention of firing at 90 degrees.  Can we please please spec this for all guns training to a maximum of least 135 degrees as this would have been the more normal scenario for dreadnoughts firing at a target either before or abaft its beam as the battle lines converge.  I am not sure what the maximum training angle was but it was certainly a lot more than merely right angles to the centreline.  The more modern Iowa Class could turn and fire through a total of 300 degrees of rotation, so 270 would not be unreasonable for WW1 ships.


(http://i1143.photobucket.com/albums/n626/bobkiralfy/battleship%20firing_zpsthambheq.jpg) (http://s1143.photobucket.com/user/bobkiralfy/media/battleship%20firing_zpsthambheq.jpg.html)   Markgraf
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 28, 2016, 01:11:31 AM
Sorry Bob...

The WIKI people suggest that the Iowa Class 16" mounts could train to approximately 300 degrees [total], however even the WIKI people [untrained journalists] fail to understand or mention any comment on non-pointing zones as these were technically classified

With my work, [Department of Defence  - Navy - Above Water Weapons Engineering] a few colleagues & I had the privilege of a 45 minute personally guided tour of BB63's 16" gun and gun control systems.....all I can suggest is that non pointing [non firing zones] were introduced to prevent shock wave damage to the vessels superstructure

I understand this is a different vessel, however this portrays some of the inaccuracies  >>:-( in WIKI reported specification etc..so research & cross referencing research detail is certainly required

Derek

Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 28, 2016, 11:39:42 AM
Turret training arcs are often given in the major reference books such as Burt and Parkes. Collateral damage to the firing ship didn't just depend on the angle of the turret but also upon the elevation of the guns. When the battleship Rodney's third turret initially fired abaft the beam at full elevation it knocked bits off the bridge structure and some of the occupants senseless!

As has been said earlier in the topic, we don't want to get ahead of ourselves in over specifying the basic system but if it can be implemented along the lines of my draft spec then for those builders who wish to incorporate gunfire effects, this could be done quite easily by programming each turret module with its pointing arcs (permissible firing zones) so that the guns would only fire when the turret was pointing within those arcs. The data could simply be held in an array and referenced against the axis of the model. A very simple additional feature I think.

Colin
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 28, 2016, 12:20:50 PM
Fair enough Colin and Derek.  All I want to see is turrets collectively training beyond the 90 degree broadside configuration.  In a model on lake scenario having turrets training thus will graphically illustrate the single central fire control system is not just multiple controls being transmitted individually.

IMO the ability to train both forward and aft facing turrets together will really make the overall visual effect truly awesome. Not sure how much we want to over complicate the programming with no fire zones, maybe just limiting rotation beyond a nominal 90 degree broadside would be more than enough.  I am thinking of actual engagement orientations at Jutland with battle lines converging.

This is getting quite exciting.  I hope the numerous calculations such as bearing computation, can this gun move to that bearing?, slowing rotation, and maybe even start and stop loops to work out will not make it over complicated.  Once the program for one turret is developed it can be copied to other channels with small timing variations edited in to reduce any ballet synchronisation effect.

Are we asking too much here ?
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 28, 2016, 12:41:58 PM
I think you can take training the turrets and the other things you mention as a given Bob. Each turret will 'know' what its limitations are as these will be individually programmed and, by the sound of it, small variations in training speed can also be accommodated to add extra realism.

As you say, quite exciting! Somebody has to be first.

Colin
Title: Re: Rotating seven gun turrets?
Post by: unbuiltnautilus on December 28, 2016, 12:42:42 PM
I think eliminating the over coordinated 'ballet' is a good point. On one of our past models ( HMS Invincible Battlecruiser ) the system used for extreme firing angles, would result in the turrets arriving at their designated firing angle at differing times. This, I think, looked much more effective than the geared together look that can be seen on some models. The arduino route seems to allow this effect to be dialled in to the design. I am watching with interest. I shall also dig out a couple of our  turrets and take some photos, you still need a mechanism after all!
Title: Re: Rotating seven gun turrets?
Post by: NFMike on December 28, 2016, 01:14:06 PM
Further to the above I'd suggest a refinement of the rotation control in addition to the speed setting, in the form of a slight delay in starting. It was mentioned earlier that the turrets are controlled individually in response to commands, so I'd suggest that part of the program would (effectively) delay the response of each turret module by a random amount between say 0 and 1 or more seconds. This is recalculated each time so it isn't always the same turrets being first, second, etc. The upper value can be an adjustable variable; setting it to 0 turns the effect off.
Title: Re: Rotating seven gun turrets?
Post by: kinmel on December 28, 2016, 02:57:14 PM
I have a Raspberry Pi 3 and an Arduino Uno and so I have added the servo control board to an order..  http://www.hobbytronics.co.uk/raspberry-pi/servo-pro-12ch

The page describes the options in detail.

Those members with either of the Microprocessors can contribute to the project by creating scripts to try various options and we can run your version for you and post the result on Youtube.

The Datasheet can be downloaded from.... http://www.hobbytronics.co.uk/datasheets/slave_servo_pro_datasheet_v01.pdf

The instructions and examples of Code can be downloaded from... http://www.hobbytronics.co.uk/tutorials-code/tutorials-microchip/hi-tech-c-i2c-master

Who is up for a joint effort ?
Title: Re: Rotating seven gun turrets?
Post by: John W E on December 28, 2016, 06:15:39 PM
Colin, one of the reasons I asked for a ‘beginners guide’ to this product was that I hoped those who endorse this particular product – i.e. Arduino boards – would come forward with their suggestions in layman’s terms for those who don’t understand and are frightened of electronics so that the majority would be able to follow. 

On this topic we may have lost approx. ⅔ of the reading members of this Forum due to them not understanding.  I believe we have a duty to cater for those who don’t grasp electronics initially when they first read the article.

Some people may not realise that this particular item can be used for other devices on the model, such as raising/lowering anchors.   Operating towing winches/using individual motors.  Also switching lights on/off in different sequences.

My opinion is, if the reader can be made aware of all the options open to using this board and how easy it can be – we must remember when we put pen to paper, those who are in the know, must take into account those who don’t.   People may be easily put off as I have said in an earlier post.
However, if we can convince them that one of these products can be as easy to wire up as an electric motor with careful guidance from a well written document by one of our members then we are on the way to helping a lot of people into the hobby.

John
Title: Re: Rotating seven gun turrets?
Post by: plastic on December 28, 2016, 06:20:47 PM
Ok - without wanting to insult anyone, I understand that this is all very clever (I'm thinking about getting one to play with myself) - but who are you going to impress at the lake?

99% of punters will be impressed that the turrets move at all. Will anyone actually notice any of the fine details being talked about in this thread?

Or is this turning into a 'navel'-gazing exercise?
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 28, 2016, 06:40:05 PM
Sorry Plastic, but surely a high degree of realism is a prime objective of building a model boat.  It is like saying no one will notice all your fine detail and workmanship, so why bother as long as it floats and goes round in circles.  Beyond this, that detail and workmanship is more for your own satisfaction rather than uneducated bystanders who cannot appreciate the amount of research you have done to get all those details right.

How it works is just as important.  When the turrets turn they should do so in a manner reflecting as far as practical how they would do so on the real ship, not just click into another position.  The purpose of this thread is to try and effect that realism, just as if we were in a spotter plane flying over the Battle of Jutland.
A worthy and useful objective IMHO.
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 28, 2016, 06:42:28 PM
 >>:-(....reading this it appears that every one is thinking about doing something, however there is still no defined plan

There is little point in providing a scope with a train requirement if is to be changed 3 times in 13 posts, so clear starting ground rules are required

a. Would a train of +15 degrees across a 180 degree broadside be acceptable?......this would the dictate a 210 degree total arc of train
b. A decision on the preferred drive to train the mounts together with physical capabilities and limits
c. Need to define an acceptable speed of turret train on axis.....would 90 degrees in 4 seconds be acceptable?
d. Need to clearly understanding the difference, interrelationship and permissives between a pointing and a non pointing zone, together with firing and non firing zones [P-NP-F-NF-Z]

From confirmation on the parameters [starting ground rules] as above, a number of control systems could be considered
 
1. Audino + conventional servo....~~180 degree limitation?...how is the turret going to be physically driven to train and increase to 210 degrees total train of arc?
2. Audino + sail winch servo.... ~~300 degree capability?... how is the turret going to be physically driven to train?
3. Audino + stepper motor..... ~~ no rotational limitation?.... how is the turret going to be physically driven to train?
4. Using P96 Servomorphs would have rotational limitations and need extra drive geometry to achieve 210 degree total train of arc, P96 units would additional software integrated for the programming of [P-NP-F-NF-Z]

The nomination for the geometry for each [P-NP-F-NF-Z] must be made .....

Bob, you will need to provide a scaled plan view of the vessel showing capital gun mounts together with principal superstructure elements, from here confirm each mounts [P-NP-F-NF-Z] in a simple spread sheet format that those penning the script or programming will understand [I could help here if you get stuck or have issues with the nominations]

This [P-NP-F-NF-Z] nomination would be a critical start HOLD point for those penning or programming the script

NB....as acknowledged on a number of occasions, my electrical knowledge is rather limited, so I see this exercise and my sole input is to assist in the planning task being completed by others for others O0

Derek
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 28, 2016, 06:43:22 PM
I do think that is a bit insulting Plastic TBH.

Would you suggest that we all build models which are just planks with Smartie tubes to simulate the guns because the average punter will never notice the difference? Where would you draw the line?

We build scale models because we like to construct models which are as accurate as possible and the Arduino exercise is no more than an extension of that. The satisfaction comes from making the model as realistic as possible including any working features. Plus it is an interesting technical challenge and any decent modeller likes to push themselves to improve their overall modelling standards. If you think it is about impressing people then you have truly got hold of the wrong end of the stick I'm afraid.

Clearly you appear to have lower aspirations but don't mock those who are prepared to put the effort in.

Colin
Title: Re: Rotating seven gun turrets?
Post by: plastic on December 28, 2016, 06:59:39 PM
I do think that is a bit insulting Plastic TBH.

Would you suggest that we all build models which are just planks with Smartie tubes to simulate the guns because the average punter will never notice the difference? Where would you draw the line?

We build scale models because we like to construct models which are as accurate as possible and the Arduino exercise is no more than an extension of that. The satisfaction comes from making the model as realistic as possible including any working features. Plus it is an interesting technical challenge and any decent modeller likes to push themselves to improve their overall modelling standards. If you think it is about impressing people then you have truly got hold of the wrong end of the stick I'm afraid.

Clearly you appear to have lower aspirations but don't mock those who are prepared to put the effort in.

Colin

I certainly don't want to insult anyone, but when you add tons of complication to a model, it just increases the chances of it sitting half-built in the shed when a problem comes up that the builder can't immediately solve.
Getting non-software people bogged down in software bugs when they are digging in the dark anyway often ends in frustration and failure.

I've seen lots of half-builts and scrapped models when the objective was above the builders technical skills.

If the objective is for something to work reliably, year after year, then, imo, simple works best.



Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 28, 2016, 07:00:53 PM
Derek, I think you are a bit behind the curve and overcomplicating things!  %) It isn't about finding the specific solution for the Agincourt now, it's about a generic solution which can be applied to the Agincourt and any other warship with movable armament. Bob has no need to supply 'capital gun mount(!)' drawings as the relevant angles can be taken from published drawings and input into each turret module as I have already tried to explain on several occasions but which some people seem to elect not to read!

Turret training speeds have already been discussed and are simply another input parameter. Extending the standard servo throw can be done with a Servomorph certainly but a single gear drive will be much simpler and easier to make (and has been made).

These are all issues which can be readily overcome, all that is needed is to combine them into a single system, it's not exactly rocket science if you understand the techniques.

I do understand that not everyone fully appreciates the possibilities that computerisation has to offer and how easy it can be for those who are conversant with the programming but believe me that our Arduino experts should be able to resolve all these issues from their familiarity with the system.

Colin


Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 28, 2016, 07:05:31 PM
Well plastic.....I do agree that there has been a number of tangential comments   {-), however I am reminded of the image of Geoff's Iron Duke below

That Q turret is stored abeam [on the vessels axis]......this turret points at the FWD superstructure.......it needs to be trained out of her non pointing zone [to either Port or Stdb] into a pointing zone which interlocks her ability to fire.....yes in a firing zone

If this were not achieved in Geoff's model & someone pressed the fire command.....the mount could blow the vessels superstructure off <*<

So to control one mount requires a little grey matter, then controlling seven turrets is a little more complex, but not x 7 fold

A few of my colleagues here in OZ are working with Audino's & pressure transducers in steam applications......so here is where my true interest with these electronic gismo's lies....

However we must be reminded that the success of any Project is only achieved and reflected by the sound plan established prior to the start of the game %)

Colin......from your comments it is clear you have never been involved in a complex project such as the refit of a warship and you are suggesting that a concept  ..."that every one is thinking about doing something" is OK ......no it's %%

Derek

 
Title: Re: Rotating seven gun turrets?
Post by: unbuiltnautilus on December 28, 2016, 07:09:36 PM
Don't degrade the joy of watching that 1% looking in wonder at your model in action. It is a gift that makes all the effort worthwhile :}
I do believe that your 1%, maybe up to 2%, will appreciate your work and effort at a typical pond edge. Take the model to a show and I would hope a vast increase in impressed onlookers.
Yes, we build to satisfy ourselves, to challenge ourselves, but also to encourage ( and let's be honest, impress ) others. It is all part and parcel of model making. If we leave a few part finished projects in our wake, so be it. You gain nothing through not trying after all.
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 28, 2016, 07:11:39 PM
Plastic, again you are missing the point! This is about simplifying the system, not involving non computer experts in debugging programs. People don't design their own speed controllers, they don't build their own ESCs. They buy them off the shelf, fit them in the model and then make limited adjustments for certain options as specified in the instruction sheet that is supplied with the device.

This would be exactly the same. At the risk of repeating myself yet again, you can have a simple user friendly program you can put on tour PC or Laptop which will take you through all the basic options to set up your turret the  way you want it. And if it doesn't do what you want then you plug it in again and make some changes.

The clever stuff is done by the designers, the builder just has to follow some simple instructions to set things up for their particular model. Bear in mind that nobody HAS to do all this. You can just glue your turrets firmly in place in a fore and aft orientation and swan around the lake in the traditional way. But I reckon that a lot of warship builders will want to put a bit of extra effort in to get some extra realism - it's called progress!

Colin
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 28, 2016, 07:13:00 PM
Derek - you are pontificating - naughty!

And I don't think you are actually reading a lot of the posts either.  <*<

Colin
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 28, 2016, 08:08:15 PM
Can I simplify this a bit please.  What we are asking for is a generic program that can operate both forward and reverse facing turrets in a realistic manner using a single Tx control, preferably with slowed turning, variable training times, possibly even start and stop loops.  For the generic program it does not need detail plans for this specific ship, merely the ability to train visibly beyond 90 degrees on either beam.

For those wishing to fine tune the system for a specific ship each of us would have to be able to see and understand the program coding, then decide how we would edit turning / firing angles for a specific vessel.
Good program writing includes 'Comments' for each part, including tips on how to customise.

Please lets not put off the kind offer of the nice developer who has offered to write a generic program.
I am willing to learn the Arduino language providing I have something written I can follow and understand.  No way I could write it from scratch.

PS:  I don't have detail plans, yet.  Maybe by mid 2017.  I aim to purchase the hull in the Spring.  The Dean's semi-kit is intended to be developed over 2017, depending on interest.  First challenge will be getting it home, then fitting the bulkheads and deck supports, running gear, method of interlocking the two halves. 

It will be built, with revolving turrets.  How to revolve them is ongoing.
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 28, 2016, 08:18:11 PM
Quite right Bob, you have summed it up very well. This, and Andy's soon to be started topic should be conducted on a positive basis. Those of us with a bit of computer knowledge know that it CAN be done so it is just a matter of tackling the various issues and getting them to work together. We should be supporting Andy in constructively resolving problems he may encounter along the way rather than diving off into side issues which may not actually be relevant and simple cause confusion.

Colin
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 28, 2016, 08:29:38 PM
Well Bob [and Colin] I too look forward to the development thread on 'any or either' software + hardware configurations that contribute and solve to a point where such systems could be used by near novice builders

I do read every word in every posting .....[unlike others but lets not go there]....and pontificating....  :o no I have always been a team member working with and toward the planned outcome :-))

Derek
Title: Re: Rotating seven gun turrets?
Post by: g6swj on December 28, 2016, 09:49:16 PM
One year ago almost to the day I carried out an experiment with a Mayhemer. I did this to learn from their learning experience.

They wanted to rotate a single gun turret on a boat.

I did a deal with them that I would supply the kit (an £8 Arduino Uno and some connectors!) if they made a donation to the RNLI upon successful completion of the project.

I also asked them to give me feedback on the process.

The experiment was a success - I emailed program updates or just description as to what to change and eventually the Mayhemer got to a level where he could see what to change to make the servo speed up, slow down, pause longer at a stopping stage etc etc.

Extract from their feedback "Well ... it now does exactly what I need it to do, and I'm happy adding sequences and varying the variables as required! "

Arduino has been designed to be a "simple and accessible user experience"

Arduino like many other programming environments allows the nitty, gritty to be hidden from the user in a library( often hundreds of lines long of code), all the user has to do is add a reference to the libray and then use the commands exposed to the user.

An example:
Quote
#include <Servo.h>

Servo myservo;  // create servo object to control a servo

void setup() {
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object
}

void loop() {
  myservo.write(95);                  // sets the servo position according to the scaled value
}
With a few lines of extra code myservo.write(95);  will make the servo go to 95 degrees - the code in the servo.h library makes it simple for the user - it's a reuseable resource freely published

Regards
Jonathan

Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 28, 2016, 09:54:24 PM
Colin and Bob have it right.

As I see it, the system breaks down into three stages:

Of these three stages, I've done #1 (for HMS Dreadnought, but can easily be adapted for other capital vessels.) Stage #3 is easy.

Stage #2 is the toughy, though I generated code to handle elements of the whole. I'm writing pseudo code now, and don't see anything insurmountable. But it IS a pile of code.

As with all software development, planning and more planning is the key to success (and not spending weeks heading off down deadends).



Andy
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 28, 2016, 10:26:16 PM
I for one am extremely grateful to you Andy.  There is no way I could even start writing something like this from scratch.  However, If I could see a completed and well annotated script I may be able to follow it enough to add my own custom edits - in time.  I have some previous experience in BASIC, Fortran, and Assembler.

What could get complicated is adding all the small variables, different for each gun, to avoid the robot synchronisation effect.  If I may suggest you write two routines, one each for a forward facing gun, and another for rear facing, otherwise you will be constantly rewriting multitudes of turret routines rather than copy/pasting them
.
When two turrets fully working, only then start editing individual turret variables. 
Sorry if this sounds egg sucking grandmas  %%
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 28, 2016, 10:29:02 PM
Basic concept demo being triggered by 3 way switch on TX - whistles and bells to follow

https://youtu.be/3BkUvv7MI8s (https://youtu.be/3BkUvv7MI8s)

Regards
C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 28, 2016, 10:43:50 PM
The book I have bought and admittedly only scanned so far suggests that the Arduino programs can work in degrees. If so then I think this will greatly simplify programming as much of the work will then be based upon simple addition. subtraction etc. and it may be possible to get away with just the one basic turret module program. Like Bob, I would be interested to see the annotated programs as while I cannot presently write the Arduino syntax, I think I can probably follow the logic of a written program.

Inevitably there will be pinch points which may need some extra thought such as the interface between the programming and the physical construction of the turret rotation mechanism in which case the practical experience of other Mayhemers may prove useful. If the 'standard' rotation mechanism can cope with the maximum likely traverse of a turret, say 270 degrees or so, then the programming can deal with the actual amount of control within that physical constraint depending on where the turret is located on the deck.

Also, publishing the initial program code may offer an opportunity for suggestions for improving or streamlining the code. There is frequently more than one way to skin a cat but often you need to see something written down first in order to identify opportunities for refining the code - certainly that was my experience.

Colin
Title: Re: Rotating seven gun turrets?
Post by: Mr.R.Duino on December 28, 2016, 10:52:17 PM
Colin,

Quote
Arduino programs can work in degrees

TRUE - Arduino programs can work in degrees or microseconds eg 90 degrees traditionally = 1500ms

Quote
There is frequently more than one way to skin a cat but often you need to see something written down first in order to identify opportunities for refining the code

SO SO TRUE!

Admin edit!  :D


Title: Re: Rotating seven gun turrets?
Post by: unbuiltnautilus on December 28, 2016, 11:28:01 PM
Basic concept demo being triggered by 3 way switch on TX - whistles and bells to follow

https://youtu.be/3BkUvv7MI8s (https://youtu.be/3BkUvv7MI8s)

Regards
C-3PO




Ahh, the beauty, the grace, the randomness of it all, the music ended far, far too soon...
I look forward to bells and whistles :-))
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 28, 2016, 11:32:15 PM
Hey that is beautiful music [for the movement]  C-3PO  :o... and the representation of the turret rotation is brilliant :-))

1. The servo speed appears to be about 90 degrees in 3 seconds......could this slowed to say 4 to 5 seconds per 90 degrees?
2. The servo swept arc appears as approximately 180 degrees total...is this already stretched?, or could the total swept arc be increased marginally?
3. We also see individual start commencement/return of certain servo's....which even by electrical skull doggery is fine

Congratulations...... Derek 
Title: Re: How to rotate several turrets?
Post by: RAAArtyGunner on December 29, 2016, 05:06:36 AM
Colin, one of the reasons I asked for a ‘beginners guide’ to this product was that I hoped those who endorse this particular product – i.e. Arduino boards – would come forward with their suggestions in layman’s terms for those who don’t understand and are frightened of electronics so that the majority would be able to follow. 

On this topic we may have lost approx. ⅔ of the reading members of this Forum due to them not understanding.  I believe we have a duty to cater for those who don’t grasp electronics initially when they first read the article.

Some people may not realise that this particular item can be used for other devices on the model, such as raising/lowering anchors.   Operating towing winches/using individual motors.  Also switching lights on/off in different sequences.

My opinion is, if the reader can be made aware of all the options open to using this board and how easy it can be – we must remember when we put pen to paper, those who are in the know, must take into account those who don’t.   People may be easily put off as I have said in an earlier post.
However, if we can convince them that one of these products can be as easy to wire up as an electric motor with careful guidance from a well written document by one of our members then we are on the way to helping a lot of people into the hobby.

John

Couldn't agree more. O0 O0 O0
Title: Re: How to rotate several turrets?
Post by: RAAArtyGunner on December 29, 2016, 05:30:47 AM
I do think that is a bit insulting Plastic TBH.

Would you suggest that we all build models which are just planks with Smartie tubes to simulate the guns because the average punter will never notice the difference? Where would you draw the line?

We build scale models because we like to construct models which are as accurate as possible and the Arduino exercise is no more than an extension of that. The satisfaction comes from making the model as realistic as possible including any working features. Plus it is an interesting technical challenge and any decent modeller likes to push themselves to improve their overall modelling standards. If you think it is about impressing people then you have truly got hold of the wrong end of the stick I'm afraid.

Clearly you appear to have lower aspirations but don't mock those who are prepared to put the effort in.

Colin

 :o :o :o :o

We are off topic, are we to believe G Guest's models, featured in the magazine "Model Boats", don't rate because they are stand off scale c'mon. Some do not have the ability and skills to create "museum" quality models and some that do choose not too.

Interesting as this topic is, some are getting their knickers in a knot, and overly complicating the issues.(the only person who "owns" the thread is our leader, Martin)

Plastic and Bluebirds comments have merit, there are those on the side who have not contributed so don't be an "bottom" and assume.

It seems to me that there is a lack of continuing/commentary from those who have previously clearly displayed ability in this area.
Title: Re: How to rotate several turrets?
Post by: RAAArtyGunner on December 29, 2016, 05:45:49 AM
Basic concept demo being triggered by 3 way switch on TX - whistles and bells to follow

https://youtu.be/3BkUvv7MI8s (https://youtu.be/3BkUvv7MI8s)

Regards
C-3PO

That looks good. O0 O0
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 29, 2016, 07:44:28 AM
Basic concept demo being triggered by 3 way switch on TX - whistles and bells to follow

https://youtu.be/3BkUvv7MI8s (https://youtu.be/3BkUvv7MI8s)

Regards
C-3PO

Now that looks awesome.  Kept watching it over and over.  Not too far off an Agincourt layout too.
90 degree rotation, both directions, opposite orientations, slow(ish) movement.
 Exciting  O0

Now I am getting into this, a question.  Would it be possible to have a 'look up table' as an array so that minor variances such as turn speed, start and stop timing values etc?  That way the generic program is the same for all turrets, with the user being able fine tune anti-ballet timing differences.

Bob K
Title: Re: How to rotate several turrets?
Post by: Martin [Admin] on December 29, 2016, 09:10:25 AM

the only person who "owns" the thread is our leader, Martin


I usually deffer to those that obviously know the subject more than I.   
 I'm only here to direct the traffic!   :police:


Title: Re: Rotating seven gun turrets?
Post by: Mr.R.Duino on December 29, 2016, 09:49:18 AM
If you want to scratch the surface a little deeper without spending a penny you could

1 - Download and install the free Arduino software (IDE - Integrated Development Environment) from https://www.arduino.cc/en/Main/Software (https://www.arduino.cc/en/Main/Software)

Once installed you could select - File / Examples/ then pick a subfolder and then a"sketch" - program to the rest of us and view the code

2- Check this out - You could experiment with an Arduino simulator - https://circuits.io/lab (https://circuits.io/lab) - create your own experiment or just load one of the ones written by others

Looks like there are hundreds of servo examples - https://circuits.io/search/designs?q=servo (https://circuits.io/search/designs?q=servo)

Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 29, 2016, 09:57:38 AM
C-3PO, thanks for posting that video, it is really helpful. Clever stuff too.

Firstly you have demonstrated a practical solution for the 3 position idea which is maybe all that some people will want. The fluctuations between the individual 'turrets' are also very impressive and it does make them look as if they are all being trained independently by the turret crews as in real life.

Secondly, your video shows quite clearly that the turrets can only all line up at 90 degrees to the beam of the vessel. At intermediate 'target' bearings the forward facing turrets are pointing in a different direction to the aft facing ones. The ability of one group of turrets to swing right round to line up with the other group is the enhancement we are trying to address in response to Bob K's original request.

I might try and get my brain in gear to attempt some rough pseudo code to try and define what is needed although it is over 10 years since I last did any programming! It is always helpful to put up an 'Aunt Sally' for others to pick holes in, it concentrates the mind!

Colin
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 29, 2016, 10:44:55 AM
The fluctuations between start time, stop time and travel speed is simple - no need for lookup arrays, seperate code etc etc - it can even be pseduo random by turret if you want.

I only have standard 180 degree servo's on hand so can't physically do the clever stuff yet - the code to allow this is not complicated and simply changing variables that allow more than 180 degrees travel is all that is required (and some new servos of course!).

I am very happy to publish my code for others to use and abuse - however to save questions on incomplete code I will wait a while so more of the functionality is implemented, I have had time to anotate the lines with an explanation etc etc. The actual code that does stuff is very short indeed - there are however many setup parameters for each servo e.g. min degrees, mid point degrees, max degrees rotation for each servo - trust me not all servos are born the same even if they are the same make and model!

My initial solution is just one way to do this - I am sticking with the common Arduino Uno for now but I am beginning to push it to it's/my limits :) - I am very interested in Andy's stepper motor version. It will be interesting to compare notes. Kinmel has also thrown his hat in the ring so look forward to updates on progress from him.

All the specification/ desired functionlity type stuff I have seen from contributors to this post should be possible with this Arduino solution.

The initial 3 way switch funtionality in video #1 was just for demo purposes

Watch this space ....

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 29, 2016, 10:55:25 AM
OK, here is my (probably pathetic) attempt to rough out the turret control code - all constructive criticism welcome!

Colin
__________________________

 Model Warship Fire Control System
Individual Turret Module
 
Note 1: It is assumed that each turret will have its own control module which accepts input from a master control board elsewhere in the model specifying the target bearing relative to the bow of the vessel. I don’t know if it would be possible to house several individual virtual modules with their own output interfaces within the master control board – if so this would reduce the component cost.

 
Note 2: Output from the turret module will directly control the actual turret operating mechanism whether this be servo based or using stepper motors.

 
Note 3: I am not including bells and whistles such as firing arcs, soft start/stop or random delay in starting etc. as these can all be added later with suitable code subroutines.

 
Fixed variables:
In this example the turret module will be pre programmed with two numbers, each of which will define the number of degrees the turret can traverse. Each number will be assigned to a direction to which the turret will train.
Thus for example:
Traverse 1 = 140 (degrees)
Traverse 2 = 130 (there is something which obstructs the full traverse on that side of the ship)

Initial variable
Turretposition=0 (turret position is along the ship centreline)

Coding.
Power= ON (the system is live and receiving data)

Start Main Loop
Do while power= ON (keep looping until data input is switched off from the main control  board)
Read target bearing in degrees (target bearing relative to the bow of ship received from main control board and contained in global variable)
Direction = ? (will be 1 or 2. Evaluate target bearing to see which side of the ship it is on)
Direction 1 loop subroutine
If  Direction=1 and target bearing <= Traverse 1
 
Do While Direction=1 and targetbearing <= Traverse 1
If Turretposition<> target bearing (then we need to move the turret)
If Turretposition< targetbearing
Output command to move turret targetbearing – turretposition degrees (move it further round)
Else
Output command to move turret  turretposition - targetbearing degrees (bring it back inboard from current position
Endif
Endif
Turretposition=targetbearing (reset turret position variable to current turret position)
Endo
Endif
Note: At this point you would have the same set of code for direction 2 although with a bit of thought the two directions could be combined into one loop but this would make it more difficult to understand for the purpose of this exercise.

Note: It would probably be necessary to re read the target bearing within the above subroutine loop as it would be continually changing and just reading it within the main loop could produce jerky movements.

ENDO (back to start of main loop)
 
Title: Re: Rotating seven gun turrets?
Post by: plastic on December 29, 2016, 11:32:18 AM
Quick question - say all the turrets are pointing to the right of the bow (including rear turrets) and the command is to point to the left of the bow. The front turrets will simply turn and point to the left.
The rear turrets cannot do that because if the superstructure blocking their path - they would have to undestand that they must travel all the way around past the pointing aft position before they can point forwards on the left side.

The same would happen with the front turrets pointing to thre rear quarters - and any midships guns would have to make decisions on which way to travel.

Will this complicate the maths because effectively, they will be rotating away from the target heading to get to their destination?
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 29, 2016, 11:36:57 AM
I believe we should get confused between maximum training arcs and regions where a particular gun cannot fire.  For the later this is not just close to superstructure or for wing turrets firing across the deck, but in superfiring turrets not being able to fire directly over the sighting hoods on the gun below (maybe +/- 30 degrees no go).

I suggest a training range of +/- 135 degrees, which could be edited in individual subroutines.

What concerns me more is what happens to a particular gun when the required bearing exceeds its training arc?   Does it stop at that position waiting for a more valid command, or return to a centreline park position.  I prefer the former option as otherwise we will have turrets rotating back and forth as the bearing swings about its end travel rotation.
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 29, 2016, 11:40:22 AM
Colin,

Looks like you've got the job! Once a programmer always a programmer - the logical approach it teaches you never leaves you.

I will read it in more detail later.

Plastic - doesn't complicate the maths - complicates the logic - but even then it's not a show stopper!

Back to my task in hand - PowerPoint slides - great joy!

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 29, 2016, 12:10:11 PM
Plastic - my rather ropey pseudo code is intended to cover the points you make. The programming can deal with the situation when guns can no longer bear. - see below.

Bob, yes - logically if the target bearing is beyond the maximum angle of traverse for a turret then the turret should stop at the limit as the bearing may shift and fall within the range as the ship 'opens its 'A' arcs to bring all turrets to bear - that is what happened in real life. Just before the Hood was sunk it was reported that one of the aft turrets was able to fire on Bismark but not the other, a minute or so later as the ship turned further all four turrets would have been able to bear.

Once you have got the basic movement geometry working then extra code can usually be added quite easily with sub routines to examine 'what if' situations and deal with them and also to remedy any unexpected anomalies that might manifest themselves with the actual behaviour of the turrets. Also, for those wishing to simulate gunfire then the firing arcs can very easily be added alongside the training data. For example a a command to stop a superfiring turret firing dead ahead might be something like:

If Between turretposition +15 degrees, -15 degrees then nofire=TRUE (Cannot fire within 15 degrees of centreline.)

As I said previously you could have more than one 'dead zone' for a turret although in most cases it would be just a single arc centred on the keel line of the ship for turrets that are obstructed by superstructure in the fore and aft position. The values would be held in pre programmed variables or arrays for the turret in the same way as for the traverse limits.

Get the basics right and efficiently programmed and all sorts of extras become easily possible on the back of them. This is the advantage of the computerised over the mechanical solution for something like this.

Colin
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 29, 2016, 12:16:51 PM
Well Colin....I would never be so condescending to suggest your work was pathetic, however I must ask why you suggested to C-PO3.....'that his video shows quite clearly that the turrets can only all line up at 90 degrees to the beam of the vessel' .....without waiting for his reply to answer a question, 'not an assertion'.....to this same to an earlier question of servo stretch in an earlier post. From this I could only assume that you do not read or understand the comments in earlier postings............

Bob...whilst I have been chastised in this thread with a number of polite expletives in being too concerned with detail......'after all it's not rocket science' we now find yourself again proposing to change the specification criteria, introducing new words....'superfiring' ...using terms left side and others talking of the term 'traverse' for a gun turret and also the highly technical nautical term of 'move it further round' or and now a 'dead zone'  {-)

Whilst reading is good for the mind, in untrained minds the same has proven to bear catastrophic results in life 

From this I am not surprised to read the latest posting from C-3PO tonight

Derek
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 29, 2016, 12:38:11 PM
Derek:  It is you yourself that decided to complicate matters by adding no firing zones to the training arcs
All I have done is to point out that no firing zones also exist outside the extremes of physical  bearing angles.  We need to leave the whole no firing zones out of the definition completely, especially as we aim to have a single control to initiate gunfire, not a multiplicity of controls such as one for each turret.

That was the initial definition, and still remains so.
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 29, 2016, 12:55:09 PM
Derek, it's not about servo stretch, it's the fact that that C-3PO quite clearly stated in his post that his video that it is a three position solution only. No amount of servo stretch is going to make the aft pointing turrets point in the same direction at the forward facing ones on intermediate bearings and it is this that some people just don't seem to be able to get their heads around. The video demonstrates this visually as opposed to me banging on about it verbally and clearly not getting through! Too many dead zones maybe?  ok2

As far as the language is concerned, Bob, I and the others are simply trying to make it understandable as not everyone is familiar with technical naval terminology although superfiring is pretty obvious I would have thought and so is traverse.

I find it very disappointing that there are some people on here who seem very keen to denigrate what we are trying to do. In your earlier post we seem to be accused of regarding people who build Glynn Guest models as somehow second rate and that we think everyone should be building museum quality models. This is in your own head and simply not true. If you cannot be positive then just watch and learn. There is no magic instantaneous solution, it has to be worked out and refined, but there is more than enough expertise on Mayhem to tackle all the various issues involved, problems will arise and can be worked through. We just don't need this endless carping from the sidelines.

Colin
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 29, 2016, 12:56:55 PM
Bob....words are such wonderful things %)...my intention was to take the initial basket full of vagaries and ambiguities out of the picture, to simplify and not complicate anything

Possibly it is best if I sit on a garden chair with C-3PO and watch progress from the sideline :-))

Derek 

Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 29, 2016, 12:59:56 PM
Mention was made earlier of 'degrees'. That draws us into the world of maths, and potentially slowing the processing by calling endless trig functions, which I thought might be required when calculating the vectors and angle between vectors. (One for the ship, one for each turret, one for the target).


My brainwave today (and they're rare enough) was that it's not necessary.


I've just proved to myself that, using a short string of if-thens and numbers alone (specifically the 4096 steps that define one rotation) I can determine whether a turret needs to turn clockwise or anticlockwise based on its training limits to reach a specific target.


Might not sound impressive, but it's going to slice out tonnes of 'ugly' when I start putting it all together.


 :-))


Andy
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 29, 2016, 01:07:38 PM
Sounds interesting Andy. As usual with this sort of thing, once the problem is defined and understood then ingenious solutions do often present themselves to those who are also familiar with the capabilities of the software and interfacing. It can be a nice feeling to cut through a lot of heavy stuff with an elegant solution.

Colin
Title: Re: Rotating seven gun turrets?
Post by: plastic on December 29, 2016, 01:14:45 PM
Is there going to be a 'park' position for returning to dock that returns all of the turrets to the original start position?

Simply specifiying straight ahead on the front turrets will confuse the rear turrets.
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 29, 2016, 01:42:30 PM
Time for peace, love and harmony!

I was just about to respond to another post when my desk picture display thingy that I was given recently showed a picture of the Hotel Negresco which I walked past a few weeks after the horrible events earlier this year in beautiful Nice.

We all want the same thing - a workable, useable solution. If an individual wants to amend the code to make the turrets dance to their own tune there is nothing to stop them.

The funny thing from my side is that I understand the Arduino/software side heaps but not a clue about the workings of gun turrets and the rules, regs, conditions, factors, no go zones etc etc

PS Andy - is the CustomStepper library (It comes with functions to make the motor rotate a given number of times, a given angle (in degrees) or rotate until you send another command) or the MAP function of use in your journey?

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 29, 2016, 01:59:48 PM
Plastic, my reply #82 on page 4. I'll have a dedicated 'park' option.


C-3PO, I haven't looked at the MAP thingmy, just played with the stepper library.


Andy
Title: Re: Rotating seven gun turrets?
Post by: plastic on December 29, 2016, 03:00:11 PM
Plastic, my reply #82 on page 4. I'll have a dedicated 'park' option.


C-3PO, I haven't looked at the MAP thingmy, just played with the stepper library.


Andy

Yes - spotted it - why 2 switches? surely just 1 switch - Off=park, on=track
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 29, 2016, 03:56:53 PM
I need to send 'target bearing' info outwith the options of 'track' and 'park'. The button will send new bearing information overwriting that held in the Arduino. Once sent, that 'local' bearing will be adjusted automatically over time as the ship's heading changes.

Andy


Title: Re: Rotating seven gun turrets?
Post by: plastic on December 29, 2016, 04:21:04 PM
Wouldn't it just sit parked until the input knob changed value for the first time?
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 29, 2016, 04:34:42 PM
I would have assumed that as Plastic says, the system would start off parked but it would be necessary to be able to to return the turrets to their fore and aft alignment at any time by a separate signal from the TX (push button?) as the TX rotary control would be dedicated to the absolute target bearing.

But then if you wished to start the system off again then another signal would be required. So in fact you need a TX control to turn the training system on or off independently of what the target setting position is. The undercarriage TX switch could do this maybe?

Colin
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 29, 2016, 05:05:57 PM
I have pondered on the switching/control issue - my simple thoughts are:

The concept I am working on involves 2 RC control channels - 1 x 3 way switch and 1 x rotary knob

The rotary knob would be used for manual rotation of all turrets - not sure how effective this will be as if moving a servo 270 degrees or so the smallest movement on the knob will move the servo quite a bit - think this will have to be suck it and see. It would be possible to use the full rotation of the knob to sweep the turrets on just the "active" side of the boat - what is the active side of the boat - don't know yet - how do you swap active sides - don't know yet :)

My thinking for the switch is:

Position 1 : Home
Position 1 : Fire
Position 2 : Manual track - use the knob
Position 3 : Auto track - whilst I will give this a go I don't know how effective this will be as without some "smoothing" of compass data the servo's will start tapping out their own tune

To clarify - at system startup all servos are returned to home position

The switch status is updated in each position.

If you return the switch to Position 1 - home for say <1.5 seconds and then switch back to position 2 or 3 the system will take this as a fire command.
If you return the switch to Position 1 - home for > 3 seconds the system will take this as a return home command

However - If this is to be a solution for all it should be able to be configured and work equally as well with a basic 4 channel 2 stick tx - which is possible - would just be a different tx implementation

PS Please excuse any typo's - I have switch to Firefox and the spill chucker has packed it's bags and gone home

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: plastic on December 29, 2016, 05:29:35 PM
I assumed it would be simpler -

off = parked

on=parked until position knob moved for first time to set target bearing - then compass keeps guns pointed at that bearing regardless of ship direction (auto mode)

off = return to park

Fire

On a simple transmitter, vertical full down = park, middle is on, full up is fire - left in full up, the guns could keep firing - maybe each turret could have a different reload time.
Horzontal = bearing set

No real need for any other modes in my opinion. Why would you need a non-tracking mode?
Or am I missing something?
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on December 29, 2016, 06:05:58 PM
Plastic - you may well be right with your logic...

I will include the manual option for now- as certainly whilst the system is created it will help with debugging - can soon be dropped.

Any feedback from other contributors re manual mode - keep? - if so what would you use it for?

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: plastic on December 29, 2016, 07:54:20 PM
You don't need a special manual mode - when the system is in its normal auto mode while sat on the desk, there no movement so there's no variable data on the compass channel - the only variable is the setting pot/stick - which is manual mode.
Title: Re: Rotating seven gun turrets?
Post by: malcolmfrary on December 30, 2016, 09:50:38 AM
A bit of a random thought - central to the operation of big gun warships was the rangefinder.  Perhaps have that rotate, "find" the target, then have the turrets keep up with it according to their programmed ability.  Or, if the target was a radio transmitter, have the rangefinder, or a directional receiver, find and track it.

Title: Re: Rotating seven gun turrets?
Post by: Mr.R.Duino on December 30, 2016, 10:25:31 AM
A bit of a random thought - central to the operation of big gun warships was the rangefinder.  Perhaps have that rotate, "find" the target, then have the turrets keep up with it according to their programmed ability.  Or, if the target was a radio transmitter, have the rangefinder, or a directional receiver, find and track it.


Radar - like this?

https://www.youtube.com/watch?v=rh6UxpzHlJI

NB Pretty amazing development board by any stadard

Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 30, 2016, 08:12:30 PM
... ten hours later ... I think you've stunned the naysayers!  %%

Meanwhile, collision avoidance is leaping to mind. Or sailing a convoy using one master vessel.

All do-able!

Andy
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 30, 2016, 08:40:55 PM
Awesome Andy  :-))  Can't wait to hear details, but I know you still have a lot of testing and debugging to do.  It sounds like you are making excellent progress though  O0

Not sure about collision avoidance etc, but we don't want to ram the target vessel !!!!
Title: Re: Rotating seven gun turrets?
Post by: Tug-Kenny on December 30, 2016, 09:35:38 PM

It tends to knock my suggestion  (in post 2)  of a rubber band into a cocked hat  %%    %%

All very clever stuff and an interesting article

Cheers

ken
Title: Re: Rotating seven gun turrets?
Post by: RAAArtyGunner on December 31, 2016, 02:57:51 AM
Radar - like this?

https://www.youtube.com/watch?v=rh6UxpzHlJI

NB Pretty amazing development board by any stadard

Very realistic. :-)) :-))
In some situations the speed is increased when searching a smaller arc, namely when the target has been identified/acquired.

Interesting to hear commentary from any Naval gunners if any on the forum???
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 31, 2016, 05:42:48 AM
RAAArty....whilst I am sitting on the sideline watching progress, however having technical training and experience in gun and director 'fire control systems' I can confirm

On a warship at sea, when the FCS director dome locks onto a target, the director body physically moves .......if we can imagine the director dome is locked onto the target, the dome does not move....it is locked

So when the vessel pitches or rolls, the directors electro hydraulic system is compensating for the movement of the vessel

In slow motion, the director is sending a continuously varying set of co-ordinates to the gun mount fire control system to compensate for the pitch & roll of the vessel

Gun mount director fire control systems were in their absolute infancy in design and use on Dreadnaught vessels.....the scholars suggest approximately only 3% of Capital ordinance firings controlled by director systems in the Battle of Jutland accurately found their mark

On modern day vessels [5000 tonnes] in a war training exercise, the barrel of a 125 mm quick fire gun mount can be visually seen to appear 'hunting in both train and elevation'. This naturally is that the dome of the director and the barrel of the mount are absolutely locked on the target despite the vessels pitch & roll

I doubt if any similar visual scenario would have been evident with the slower movement of 12" or 14" guns on Dreadnaught vessels of 25000 tonnes

Derek
Title: Re: Rotating seven gun turrets?
Post by: raflaunches on December 31, 2016, 08:51:52 AM
From what I've read so far on the subject of Dreadnought era gunnery and firing the fire control director tower housed the optical sights and possibly the mechanical range finder computer (Dreyer Table). In that era the director didn't directly control the turrets like they do today but gave the range to the turret gun crew who then moved, elevated or traversed the turret in to the firing position. Essentially they were lookouts with a radio telling the turret crews where to aim. So whilst it looks pretty for all the turrets to move as one it may not always be true.
I stand be corrected and learn but that was how Dreadnought's turrets worked from what I've read.
However I'm not a buzz kill and find this thread fascinating and it would look spectacular working on Agincourt or any other warship model. Keep up the good work. :-))
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 31, 2016, 09:15:56 AM
I still find it amazing that capital ships of that era could hit anything at all with their voice commands plus  pointers and graduated scales inside the turrets.  Agincourt did not even have a Dreyer Table at Jutland, she fired 144 shells yet no recorded hits.  Firing was probably limited to 'top of the roll'.  Thinking was to a degree still Nelson era too, close battle lines to 6,000 yards and blast away.  In practice the range far exceeded this where meaningful accuracy was beyond the limits of equipment available.  British hits were only 2.7%.
Gun elevations seemed to vary greatly, almost at random.  Maybe due to recoil effects and the mechanics of loading?

It is just when you look at a Challenger 2 tank firing accurately whist travelling at speed over rough terrain . . .
No comparison
Title: Re: Rotating seven gun turrets?
Post by: malcolmfrary on December 31, 2016, 09:50:06 AM
Radar - like this?

https://www.youtube.com/watch?v=rh6UxpzHlJI (https://www.youtube.com/watch?v=rh6UxpzHlJI)

NB Pretty amazing development board by any stadard
Streets in front of what I imagined - I was thinking that a rotating directional aerial inside the superstructure could "find" a transmitting target carried by either a target ship or somebody on the bank (sort of doing the lookout job) then the arduino could tell the director/rangefinder where to point then the turrets.  It is 1916 technology that is trying to be simulated as a special effect on a model, so really, as with most of the things we do, it is an effect rather than an actual event that is wanted.
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on December 31, 2016, 10:11:31 AM
Quite right about the rather rudimentary director control methods in use at Jutland. The Gunnery team in the foretop would transmit the range and elevation to the turrets using electrical pointers. The turret crews would line up on those pointers and I think the guns could then be fired from the foretop, as Bob says, 'on the top of the roll' when the ship was level. Gunnery officers hated course changes as it meant they had to re lay the guns and start again just as they were 'getting their eye in'.

There is one other thing I don't think has been mentioned and that is, while the guns could be loaded on any bearing and any any elevation, in practice loading at elevation was slow as the rammers had to push the shell and cordite bags uphill so a common practice was that after the gun had fired it was lowered almost to the horizontal for loading and then re elevated. This process was much quicker. You can see the guns dipping after firing in many films of gunnery exercises.

NB: I'm not suggesting we should go so far as to emulate this though!

Colin
Title: Re: Rotating seven gun turrets?
Post by: plastic on December 31, 2016, 04:03:56 PM
It would be very simple to build 2 types of module smaller than a matchbox with a pulsing I/R LED to drop onto the decks of 'goodies & baddies'. to designate ships.

Choose 2 separate frequencies for friend or foe and have the detector on the warship look for, lock onto and aim the guns at.

A simple binocular detector that rotates until both detectors give the same o/p signal will give you the heading to the I/R source - and should stay locked regardless of movements of both ships.
If you have multiple ships, it would be interesting to watch the guns re-train on the next target when lock is lost on the first ship. The same detector could identify 'hits' from the other vessel if the guns had I/R LEDs and were pointing exactly towards it. If the detectors could differentiate more than 2 frequencies, a counter could decide when the ship has had too many hits and is out of commision. Game over.
Title: Re: Rotating seven gun turrets?
Post by: srcampb on December 31, 2016, 06:03:09 PM

"It is 1916 technology that is trying to be simulated as a special effect on a model, so really, as with most of the things we do, it is an effect rather than an actual event that is wanted."


I fully agree, and can't wait for the January thread on development.. Thanks!!
Title: Re: Rotating seven gun turrets?
Post by: unbuiltnautilus on December 31, 2016, 06:39:02 PM
Radar - like this?

https://www.youtube.com/watch?v=rh6UxpzHlJI (https://www.youtube.com/watch?v=rh6UxpzHlJI)

NB Pretty amazing development board by any stadard




Very impressive, although I feel that at our local lake, as you lower the model into the water, someone would nick your laptop :}
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on December 31, 2016, 08:44:29 PM
I still find it amazing that capital ships of that era could hit anything at all ...


Me too, though I suppose it largely boils down to spotting splashes (over, under), adjusting, using a Dreyer table, and following it up with the sheer volume of fire. It's interesting that only 24 years later, that old Jutland veteran HMS Warspite manages a hit at around 26000 yards using radar: technology we're more attuned to, which (perhaps) makes successful gunnery more 'obvious' to us.


Andy
Title: Re: Rotating seven gun turrets?
Post by: Mr.R.Duino on December 31, 2016, 09:22:47 PM
IR TX RX

https://learn.sparkfun.com/tutorials/ir-communication

https://www.youtube.com/watch?v=iFpAqG90zY0
Title: Re: Rotating seven gun turrets?
Post by: derekwarner on December 31, 2016, 09:55:33 PM
As Colin notes.......

'so a common practice was that after the gun had fired it was lowered almost to the horizontal for loading and then re elevated'

This is correct as loading was limited to a few degrees +/- of horizontal as the axis of rammer assembly is fixed within the gun mount....

...'and I think the guns could then be fired from the foretop',.....well the Order to fire was given by the Senior Weapons officer in the Fire Control unit in a bunker down below in the vessel....this Order was relayed to the individual gun Captain in each mount [who only after confirmation of train and elevation bearings were established] relayed the Order to the Firing Officer ...& finally to a Weapons Seaman rating who moved a lever & pressed a button

All of this voice communication in each mount was relayed back down to the Fire Control unit where exact references to train & elevation together with knowledge of each charge weight and projectile were 'mumbo jumbled' and then compared to the reported accuracy of fire.....however, 'the guns could only be fired by electro mechanical function in each mount'....

Would need to take a cut lunch before firing could commence....... Derek

 
Title: Re: Rotating seven gun turrets?
Post by: Bob K on December 31, 2016, 10:36:04 PM
How the Arduino prototype looked in 1918.   (Dreyer Fire Control Table)

(http://i1143.photobucket.com/albums/n626/bobkiralfy/dreyer%20fct_zpszg1eue3s.jpg) (http://s1143.photobucket.com/user/bobkiralfy/media/dreyer%20fct_zpszg1eue3s.jpg.html)
Title: Re: Rotating seven gun turrets?
Post by: ballastanksian on December 31, 2016, 10:59:52 PM
I expected it to look more like Babbages Difference engine but in a metal case with knobs for input and dials for output. The Dreyer table looks like a 2D Plotter which may well be how it outputs information?
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 01, 2017, 04:22:45 PM

I have so far been pursuing a solution using servo's - whilst this has in the main been successful it does have some challenges to overcome.

When you track a target the servo movement can be "jittery" - this has nothing to do with the Arduino - simply the fact that you keep asking the servo to move to a new point as the boat changes orientation - even with smoothing I have not achieved an acceptable smooth movement yet - still options to exhaust - May have to use a PID controller

Another physical challenge is protecting your compass sensor from "magnetic interference" - anything else that's ferrous or has a magnetic field - the compass sensors are super, super sensitive and can smell a servo within 6-12 inches proximity

So I dusted off some stepper motors and gave them a blast but came up with a technical problem that I can't see the solution too without additional work (calibration each power on) - maybe there is an obvious solution.

The stepper motor has no "position feedback" mechanism. It simply steps X steps in either direction as and when it's told to. So whilst you could manually align several steppers at the start it's possible they may drift in alignment over time.

But take this scenario - power disconnects from Arduino when they (steppers) are not in "park" position - how do you tell them to go back to park? they have no idea where they are at power on?

Andy - do you have a solution for this one? - Have I missed the obvious? - wouldn't be the first time :)

Does this simply mean that you would have to "calibrate" the system each time you "power on" so they know where home is?

I think driving 7 steppers from one Arduino could be interesting...

So as always one step forward, three quarters back

*-*-*-* Happy New Year *-*-*-*

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on January 01, 2017, 04:35:38 PM
 
What sort of price are small stepper motors?
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 01, 2017, 04:40:32 PM
Prices vary depending where they come from

approx £<10 for 4

http://www.ebay.co.uk/itm/401107384327

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on January 01, 2017, 04:49:51 PM
 
OK, cheap enough!   :-))

Could you use a micro switch to register a 'home' position?
Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 01, 2017, 05:00:45 PM
I think driving 7 steppers from one Arduino could be interesting...

C-3PO

C-3PO.  In my case ( 7 turrets ) there will of necessity be two systems, one for each split hull half, with a separate Rx in each half, and I suppose separate compasses too.  ie:  No servo leads to keep disconnecting between hulls. 

As I suspected the solution is not as easy to achieve as previously supposed.  Sorry to cause grief.

Bob K
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 01, 2017, 05:07:16 PM
Martin,

Yes I am sure you could use micro switches - it just adds another level of complexity of both build and sensing - I think it could be tricky to get switches aligned so you get guns aligned in park position

Maybe a rotary encoder - but again more hassle!!

I am playing with driving "2 servo's as one"  -  2 standard servos attached to each other to get 360 degrees movement which gives the positional feedback

Could just use a 1.5 turn sail servo of course but I don't have any of those in my junk box...

Bob - I honestly think the "system split" between 2 hulls is something to assess at the end of the journey as who knows what the most elegant solution to that may be as the basics have yet to be defined and decisions now could easily change - all part of the fun.


C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on January 01, 2017, 05:26:47 PM
I would agree that the split hull issue is peripheral to the generic solution. Bob. you are going to need physical connections to join the two halves of the hill together anyway. There are many multiway locking connectors on the market with reliable twist locks and other quick connect/release mechanisms so utillising perhaps a couple of these would not really add to the complexity of attaching and detaching the two hull halves and could make life a lot simpler.

With regard to jittery servos, if it is the servo itself that is the problem then more expensive servos may be the solution such as these: http://www.hyperion-world.com/en/p1005985-hp-ds20
A quick search online suggests that others have encountered this issue when trying to set up remotely controlled cameras which also need a very smooth action with no jitter.

Colin
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 01, 2017, 05:54:53 PM
Hi Colin,

Re jittery servo - the cause I believe is that I am simply telling it to frequenty to move little amounts - there are quite a few ideas yet to exhaust with this challenge

I am going to go back to basics and look at the signal supplied to make servo sweep smoothly and see if I can glean update rate etc from that and then simply duplicate what I find.

Re the 2 hull bit - my original suggestion was along the line of a Master and Slave unit - they could talk to each other through the bulkhead without any physical connection either by radio or by light/IR if a transparent "waterproof" window was created on both joining faces of the hull.

Or perhaps a magnetic multiway connector like the ones on the current MacBook's which are super clever

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on January 01, 2017, 06:02:01 PM
Yes, plenty of connection options I would have thought, your suggestions are interesting.

Just been looking around and there is a lot of stuff about smoothing servos such as this extract: http://forum.arduino.cc/index.php?topic=19367.0

I expect I am trying to teach you to suck eggs though and I take your point about sending too frequent signals to the servo. I suppose it is really a question of finding the right combination for the electronic and mechanical parts of the system to 'mesh' efficiently.

Keep up the good work.

Colin
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on January 01, 2017, 06:08:05 PM
The stepper motor has no "position feedback" mechanism. It simply steps X steps in either direction as and when it's told to. So whilst you could manually align several steppers at the start it's possible they may drift in alignment over time.

But take this scenario - power disconnects from Arduino when they (steppers) are not in "park" position - how do you tell them to go back to park? they have no idea where they are at power on?

Andy - do you have a solution for this one? - Have I missed the obvious? - wouldn't be the first time :)

Does this simply mean that you would have to "calibrate" the system each time you "power on" so they know where home is?


Re: drift - they won't. They're driven by step counts, and if not stalled or 'over-clocked', they will continuously 'know' where they are.


Loss of power will leave the steppers pointing in random directions, and - short of a 'self diagnostic' reset requiring microswitches, which I think will over-complicate things, I'm aiming to use the 'thirty-second warm-up' period for the compass to allow the user to set the park position (by use of the target bearing pot and a switch) turret-by-turret.


Meanwhile, it's great to see posters coming up with the same potential issues that I'm working though. Nothing's lurking under the bed, so far!


Andy
Title: Re: Rotating seven gun turrets?
Post by: malcolmfrary on January 01, 2017, 06:50:14 PM

Re: drift - they won't. They're driven by step counts, and if not stalled or 'over-clocked', they will continuously 'know' where they are.


Loss of power will leave the steppers pointing in random directions, and - short of a 'self diagnostic' reset requiring microswitches, which I think will over-complicate things, I'm aiming to use the 'thirty-second warm-up' period for the compass to allow the user to set the park position (by use of the target bearing pot and a switch) turret-by-turret.
Printers are usually driven by steppers these days, and on a "just in case" basis have switches to sense the end of travel to avoid that horible noise that they make when they try to drive through the end. 
Servos, or a stepper driving a position sensing pot, and incidentally a turret, could automate the process.  The pot position could be read via an ADC, I assume that such things are available for Arduinos?  Effectively, re-inventing the servo, but with an Arduino providing the control electronics.
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 01, 2017, 07:26:06 PM
The pot position could be read via an ADC, I assume that such things are available for Arduinos?  Effectively, re-inventing the servo, but with an Arduino providing the control electronics.

Malcolm,

Arduino Uno has 5 dedicated Analogue ADC/DAC pins which can be configured as either input "read" or "output...

Most pots unless you spend lots only have a maximum travel of 300 degrees or so - hence rotary encoders would work better ...

Whilst I am a complete advocate of Arduino's they are not multi taskers and every additional thing they are doing is asking more of the little beast.

However if more umphh required could use Arduino Mega or my favourite the Arduino Due or Teensy running Arduino code ( Teensy v3.6 features a 32 bit 180 MHz ARM Cortex-M4) or indeed switch to ARM Cortex M4 development boards - and you would be cooking on gas in a multi-tasking environment - puts the poor Arduino Uno 16mhz version into context ...

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on January 01, 2017, 08:28:35 PM
...Effectively, re-inventing the servo, but with an Arduino providing the control electronics.


 :-))


I've thought about this for home-brewed, industrial-strength sail winches. A stepper motor driving a worm gear (meaning any force on the output can't easily force the stepper) with a rotary pot being 'read' for position info. It could be compact and capable, and no problem to code for differing requirements.


Andy
Title: Re: Rotating seven gun turrets?
Post by: Allnightin on January 01, 2017, 08:31:26 PM
I had a go at a similar system almost 20 years ago as a final project for a HNC course.  The main concept was to have a 8 bit binary register that counted up and down from a preset starting count which represented the forward facing turrets pointing forward.  Moving the control stick resulted in the counter going up or down.  The counter was linked to a Digital to Analogue converter so that a change in count became a change in voltage output.  This was input to an Op amp circuit that  drove a small motor via a simple worm drive to move a small potentiometer (ie a DIY DC servo).  The advantage of this was that the servoes were small, light and cheap and could easily be made to cover whatever arc of movement that was required by using a different gear reduction ratio.  Training limits were controlled by having seperate Op amp comparators (2 for each servo channel) also taking the DC signal and their output arranged to override (via a multiplex circuit) the main signal and take the servo to a park position or just freeze it until the counter came back within the limit of free movement. 

A seperate 8 bit counter with a different preset starting count is linked to the same RC channel input so it counts up and down in coordination with the first one but maintaining a fixed difference in output.  This allows the aft facing turrets to move smoothly through the right astern position while the forward facing turrets are in park or freeze positions.

This system meant the turrets were actually stepping at about 1.4 degree intervals and the full 360 degree circle would be covered in about 5 seconds if the training command was continuosly applied in one direction.  This was OK for a demo but it would be simple enough to increase to 10 bit counting to give about 0.4 degree resolution and 20 seconds for 360 degrees.

This was all implimented in dedicated specialist function ICs and I spent a lot of time getting the interface between different parts to work reliably and ran out of time to iron out a few anomalies before I had to present the system as it was.  I meant to return to it and convert to a more computer based version (probably using PICs) but got sidelined by the 1/32nd Type 42 record attempt so never took it any further.  I do know that the DC servo bit worked well and can pass on details if anyone wants to follow that aspect up.  The specialist ICs used for the counter are almost certainly out of production so I would doubt that side is worth considering but perhaps the overall concept of two registers with a fixed relationship would be a good starting point for implimenting via Arduino(s) or similar?
Title: Re: Rotating seven gun turrets?
Post by: unbuiltnautilus on January 01, 2017, 11:54:44 PM
As promised, turret rotation mechanics from some of our models. These are built heavily, as they have to operate quite hefty pyrotechnic effects. They are also very 'old school' compared to systems being discussed here. However, they may provide some ideas for the basics of the mechanics.
The first unit uses microswitches and diodes to drive to a pre-selected position, then stop when that position is reached. This system allowed the selection of any of six positions plus fore and aft rest positions. If a particular turret had no microswitch on a selected bearing, it would not respond. Only moving when a valid position was selected. The electrical system used to select, command and stop the turrets was based on the electrical circuit used to select floors when you use a lift!
Title: Re: Rotating seven gun turrets?
Post by: unbuiltnautilus on January 02, 2017, 12:06:24 AM
The second design was simplified so that more members could build them. It uses a geared motor to directly rotate the upper plate. It only has two limit switches fitted, equipped with diodes to stop the turret if it attempts to drive beyond it's stops. The turret can be stopped at any position, as well as at it's end stops. The offset gearbox casing in red, provides the cam effect which engages the microswitches.
The limitation of this system, as previously discussed, is that on any angle of traverse that is not 90 degrees to port or starboard, the fore and aft turrets are pointing in different directions.
We also have a variation on this version driven by 1/4 scale servos. These have had to be fitted with a rubber shock absorber in the drive train, otherwise we run the risk of stripping the gears when using the pyrotechnic effects. These were built before Actions Servo Morph was introduced. We have yet to marry up the servo driven units to some of these, so cannot comment on their suitability.
As I said previously, these units are not the latest tech, but hopefully something in their design may help with the hardware side of this project.
Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 02, 2017, 07:55:09 AM
When the words Portsmouth and Pyrotechnics are combined I assume that these are from ships taking part in the wonderfully realistic battle displays we all admire at numerous Shows.  Really interesting to see how it is actually done inside.  Thank you.
Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on January 02, 2017, 09:42:06 AM
 
As there are now two topics covering roughly the same topic,
 I'm therefore moving this top into same area as other topic so we can follow both topics with avid interest!  :-))
 

Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 06, 2017, 01:36:20 PM
Hi,

If you were interested in this thread and thought things had gone very quiet.... well going back to work slowed things down a little - however lots of activity behind the scenes.

Coming soon my concept of a solution - also Andy now has a seperate thread where he will be posting his updates http://www.modelboatmayhem.co.uk/forum/index.php/topic,56884.msg591153.html#msg591153

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: RAAArtyGunner on January 07, 2017, 03:40:57 AM
Yes,

It was getting suspenseful, O0 O0
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 09, 2017, 10:03:08 PM
Video shows movement of 7 turrets being controlled by a sensor connected to an Arduino

https://youtu.be/dfrxhtwXMoQ (https://youtu.be/dfrxhtwXMoQ)

Fine tuning required......

Regards
C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on January 09, 2017, 10:12:52 PM
Impressive!

Colin
Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 09, 2017, 10:20:40 PM
Now that looks to have real potential.  :-))
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 09, 2017, 10:30:41 PM
I have learnt quite a lot in a short time!

One thing that I think will work really well relates to the alignment issue of using stepper motors.

As you have no physical position feedback mechanism with a stepper motor an alignment process is required at the start up of the system.

This could be a very complex set of controls to "electronically" move steppers into a calibrated position.

My solution currently involves drinking straws cut down and pushed onto the stepper motor shaft. There is enough friction that they hold their position but you can very simply manually move them to line up with each other (place in "park" position at start up) by just moving them with your fingers.

There is an added benefit to this - in event of a system failure (perhaps a wire came off) then should the motor continue to rotate as soon as the gun barrel touches any part of the super structure it would stop and allow the motor shaft to rotate without causing any damage (stepper motors have got some serious grunt!) - I would suggest this "friction fit" solution is a very elegant, fast solution to the alignment process.

I am sure there something better than just the humble straw to achieve this....

Regards
C-3PO
Title: Re: Rotating seven gun turrets?
Post by: g6swj on January 10, 2017, 09:18:00 AM
This video has some interesting info - it also has a really neat 3D printed "connector" for the 28BYJ stepper shaft.

https://www.youtube.com/watch?v=0TNBxt5hF-g (https://www.youtube.com/watch?v=0TNBxt5hF-g)


Looks like you can download 3D print file for this type of wheel from various sources https://www.thingiverse.com/thing:1115947
Title: Re: Rotating seven gun turrets?
Post by: g6swj on January 10, 2017, 10:14:22 AM
Forgot to post - Stepper motor supply - hundreds of places to buy steppers but often not UK stock

Not the cheapest but if you have Amazon Prime then these are a good deal - I ordered some - they arrived next day

6 x 28BYJ steppers (including driver board) £12.99 or £2.17 each!

https://www.amazon.co.uk/gp/product/B01HEQY760/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

Title: Re: Rotating seven gun turrets?
Post by: ballastanksian on January 10, 2017, 09:18:39 PM
The smooth movement of the stepper motors and the delay in reacting to the directors instructions are very realistic. There would be an appreciable delay when and if the director was ordered to change target quickly and the turret controller had to move the mechanism to regain a match with the dial.

Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on January 10, 2017, 10:56:58 PM
This video has some interesting info - it also has a really neat 3D printed "connector" for the 28BYJ stepper shaft.

https://www.youtube.com/watch?v=0TNBxt5hF-g (https://www.youtube.com/watch?v=0TNBxt5hF-g)


Excellent find!   :-))
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 11, 2017, 10:02:25 AM
Starter for 10...

I want to configure the turret rotation limits and non-fire zones based on HMS Agincourt.

I want to stress that these will be changeable by the user and I don't want to start a massive debabte as to what's right and what's wrong - I just want a sensible starting place and do not have that knowledge.

So Bob / Colin would you perhaps be able to give it your best shot ( excuse the pun!)

As per my image below - for guns marked A,B,C,D,E,F,G could you suggest for all guns (assume ship is heading due North):

So example Gun A might be

Re reading my post - the text is a bit clumsy but I think you will get what I am after...

Thank you in advance

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on January 11, 2017, 11:16:23 AM
 
( NB: Interesting read about Sultan Osman I / HMS Agincourt  on Wikipedia - https://en.wikipedia.org/wiki/HMS_Agincourt_(1913) (https://en.wikipedia.org/wiki/HMS_Agincourt_(1913))  )

The rate of fire of these guns was 1.5 rounds per minute. When a full broadside was fired, "the resulting sheet of flame was big enough to create the impression that a battle cruiser had blown up; it was awe inspiring." No damage was done to the ship when firing full broadsides, despite the common idea that doing so would break the ship in half, but much of the ship's tableware and glassware did shatter when Agincourt fired her first broadside.    :o
Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 11, 2017, 12:33:24 PM
Excellent, and necessary, question C-3PO.    However …
I do not yet have a set of plans, so your impressions from your diagram will be as good as mine.

You have numbered the turrets A to G, with A aft-most.  They were numbered 1 to 7, staring from the bow.  For the purpose of this I will use your annotation, and give degrees either side of the normal “park” position.
Note:  “0'” park positions foreward for G, F, E, C.   Aft for D, B, A.   A, b & D rotate opposite to G, F, E, C

G:   training +/- 150 ‘.  No firing, directly ahead, say +/- 20’, and beyond +/- 140’
F:   training  +/- 150’.  No firing over hood below +/- 30’, and beyond +/- 140’.
E:  training between 25’ and 150’ either side.  No firing 10’ inside this either side.
D:  training between 30’ and 150’ either side.  No firing 10’ inside this either side.
C:  training between 25’ and 150’ either side.  No firing 10’ inside this either side
B:  training  +/- 150’.  No firing over hood below +/- 30’, and beyond +/- 140’.
A:  training +/- 150 ‘.  No firing, directly astern, say +/- 20’, and beyond +/- 140’

Mostly guesswork I admit, but hopefully a starting point
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 11, 2017, 04:02:03 PM
Bob, thanks for this - it's a good starting point

I had to smile - forget rotating 7 turrets - rotating the image I captured by 180 degrees before I started lettering would have been a smart move - sorry for the confusion.

Regards
C-3PO
Title: Re: Rotating seven gun turrets?
Post by: RAAArtyGunner on January 12, 2017, 01:36:31 AM
C-3PO,

To simplify the code and any future user changes to suit other applications may I suggest the following as a good starting point.

Using your layout all forward facing turrets traverse 270 degrees to 90 degrees. The bow being due north, namely 0 degrees.
In other words 90 degrees traverse port to starboard. One set instructions for forward turrets. No fire zone, 91 degrees to 269 degrees. Not able to fire rearwards, towards stern.

It follows the rear (stern) facing turrets would differ by 180 degrees.
Namely traverse 90 degrees to 270 degrees with no fire zone 271 degrees to 89 degrees. Once again not able to fire rearwards that is towards the bow.

Don't know much about programming but you then apply one of the two "codes" to each turret.

Am I missing something  ?????
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 12, 2017, 09:09:28 AM
RAAArtyGunner,

You say you don't know much about programming but your approach is very logical and makes complete sense re the two sets of code - one for forward facing, the other for rear facing gun turrets.

My concept allows each turret to be configured individually - however to create this I have created code as you state above and then simply copied it and the tweaked for the additional turret configurations.

Clearly the "code" will not suit all ship configurations but hopefully will be easy to understand (fully documented) so a user (can always ask for help on here) can take the core code and then modify it to suit their own use.

I have been programming on and off for nearly 38 years and still get a kick out of solving a logical problem and then implementing it successfully in code - and I still find that I learn new things most weeks which is also quite satisfying.

I dabble with this when time permits simply to keep my my mind active - the thought process / problem solving activity seems to take place when dog walking, washing up, watching tv, talking to the wife

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on January 12, 2017, 12:15:21 PM
 
                  {-)
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 12, 2017, 12:27:32 PM
Bob/Colin...

I have pretty much finished this - just need to refine the code - remove any stray development code and optimise it's performance and complete final testing and then document to save lots of questions.

I am about to move onto the whistle and bells aspect - allowing simulated gun fire to be triggered from the TX (sound and light & smoke)

I also have thought about incorporating azimuth control - additional steppers.

I have no understanding of the sequence of events re azimuth movement of a gun - indeed real world and model simulated world may be different.

Would you want the gun to automatically move down after a shell has been fired to allow/assist reload?
What angle would it train down / up to?
Is there any kick (movement of turret/ or gun in the turret) as the shell is fired?
Would you simulate auto down after fire and then auto up to perhaps different angles per turret to allow another shell to be fired?

Regards
C-3PO


Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on January 12, 2017, 12:42:45 PM
For the period we are looking at and starting with a loaded gun run out ready to fire:

The gun fires and recoils.
The gun is then run out by hydraulics, compressed air or springs and is immediately lowered to the loading position, typically 2 to 5 degrees in elevation. (Agincourt had a fixed 5 degree loading position).
The gun is then loaded and re elevated to the firing position.

To add to the complication, guns were typically fired in salvos so in a twin turret the guns would fire alternately. Broadsides, with all guns firing at once, could, and were sometimes used, (Agincourt at Jutland) but this tended to strain the hull and structure and cause additional blast damage. Salvoes also aided ranging on the target as there was less of an interval in firing at it which helped in making corrections.

The issues in simulating all this would lie in the mechanics rather than the computer code I think! A lot of mechanism to cram into the turret. Still, the code could be there if somebody wanted to use it.

You would also need to know the 'range to target' which would dictate the maximum elevation of the gun but again this could be optional as with the other bells and whistles items.

Colin
Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on January 12, 2017, 12:53:58 PM
I have pretty much finished this - just need to refine the code - remove any stray development code and optimise it's performance and complete final testing and then document to save lots of questions.

I am about to move onto the whistle and bells aspect - allowing simulated gun fire to be triggered from the TX (sound and light & smoke)

Regards
C-3PO

I noted that ion Ralph's video, he 'shuts down' the stepper motors, when not in use, to save battery power.....
 
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 12, 2017, 01:01:40 PM
Quote
I noted that ion Ralph's video, he 'shuts down' the stepper motors, when not in use, to save battery power.....

Martin - Yup  a must - if you can see any of the LED's glowing on the little driver boards you can guarantee the stepper motor is energised and getting warm

Colin - engineering/mechanics is not my strong point - the steppers are pretty small - maybe they could be mounted below deck - the azimuth control either with push rod or belt driven

A quick after thought - the steppers are quite heavy and I am sure the closer to the keel the better to stop a top heavy model - over to the engineers/mechanics to solve...

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 12, 2017, 02:47:48 PM
Those steppers are incredibly small, hopefully "man enough" for the job.
From a practical point of view there really is no need for gears or rubber bands.  A simple 1:1 shaft connection on the same axis as the barbette centreline.  This also keeps the stepper low in the hull and makes access easier.
Maybe with a rubber tube "prop shaft coupler" for mechanical safety.

I too envisage two similar sub routine sets, one each for whether park position is forward or aft facing.

If each turret sub routine contains a set of "commented" and editable values for the max/min rotation and firing limits users (like me) can edit those to suit the local requirements for that particular turret.

If this is anything like other programming languages I have used there should be the ability to set both global and local variables, the former to calculate common values such as bearing, the later to set (eg) turret B rotation limits.
Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 12, 2017, 02:59:54 PM
You would also need to know the 'range to target' which would dictate the maximum elevation of the gun but again this could be optional as with the other bells and whistles items.

Colin

All getting too complicated.  Next may be suggested using "range" to calculate the slight convergence between guns at each end of the ship.  In practice lack of accuracy relied on a degree of spread in the fall of shot. ie:  All pointed in the same direction / elevation for a centrally commanded range.
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on January 12, 2017, 03:08:08 PM
I agree, a fixed elevation would be sufficient for a model. Most of these ships could only elevate to around 15 degrees anyway.

But if you were actually proposing to shoot somebody...... :o

Colin
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on January 12, 2017, 03:10:56 PM
Given the volume available below the turret and within the barbette diameter at 1/72nd/1/96th scales, I suspect there's enough room for pretty much anything in terms of additional functions. The turret could be seen as just a mechanical "head" for the guns' recoil and elevation.


Andy
Title: Re: Rotating seven gun turrets?
Post by: g6swj on January 12, 2017, 03:15:04 PM

If this is anything like other programming languages I have used there should be the ability to set both global and local variables, the former to calculate common values such as bearing, the later to set (eg) turret B rotation limits.

Bob - The Arduino language is based on C/C++ so you are quite right it can have a configuration section where all the variables can be set

Quote
Those steppers are incredibly small, hopefully "man enough" for the job.

Because of the internal gear box they have some serious grunt - I would suggest much more than a normal servo - I don't think you would be able to stop rotation with your fingers - I will try this out

Generic 28BYJ specification
Rated voltage : 5VDC
Number of Phase 4
Speed Variation Ratio 1/64
Stride Angle 5.625° /64
Frequency 100Hz
DC resistance 50Ω±7%(25℃)
Idle In-traction Frequency > 600Hz
Idle Out-traction Frequency > 1000Hz
In-traction Torque >34.3mN.m(120Hz)
Self-positioning Torque >34.3mN.m
Friction torque 600-1200 gf.cm
Pull in torque 300 gf.cm
Insulated resistance >10MΩ(500V)
Insulated electricity power 600VAC/1mA/1s
Insulation grade A
Rise in Temperature <40K(120Hz)
Noise <35dB(120Hz,No load,10cm)
Model 28BYJ-48 – 5V

Regards
Jonathan
Title: Re: Rotating seven gun turrets?
Post by: g6swj on January 12, 2017, 03:33:00 PM
This a complete program to control a stepper - maybe it will help dispel some of the myth - it's not the greatest - but it does work (never, ever, ever use the delay() command - it's a bad habit and will cause you heartache/ high blood pressure at some point)
All text preceded by the double slash // is remark/comment documention/ explanation text and is not an part of the actual program commands

Quote
#include <Stepper.h>

const int stepsPerRevolution = 200;  // program variable - change this to fit the number of steps per revolution
// for your motor

// initialize the stepper library on pins 8 through 11:
Stepper myStepper(stepsPerRevolution, 8, 9, 10, 11);

void setup() {
  // set the speed at 60 rpm:
  myStepper.setSpeed(60);
  // initialize the serial port:
  Serial.begin(9600);
}

void loop() {
  // step one revolution  in one direction:
  Serial.println("clockwise");
  myStepper.step(stepsPerRevolution);
  delay(500);

  // step one revolution in the other direction:
  Serial.println("counterclockwise");
  myStepper.step(-stepsPerRevolution);
  delay(500);
}

And without the Serial.print which sends text to your PC screen via the USB port (mainly used for debugging) or the comment text it looks like this - not much to it!


Quote
#include <Stepper.h>

const int stepsPerRevolution = 200; 

Stepper myStepper(stepsPerRevolution, 8, 9, 10, 11);

void setup() {
 
  myStepper.setSpeed(60);
 
}

void loop() {
 
  myStepper.step(stepsPerRevolution);
  delay(500);

 
  myStepper.step(-stepsPerRevolution);
  delay(500);
}
Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 12, 2017, 03:57:01 PM
Well, I can follow that syntax as you have written it.  The helpful remarks/comments make it easier to identify what value to edit, if required.   I never did C or C++, but the logic involved is clearer when written as you have done.
Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on January 12, 2017, 04:28:04 PM
 
NB: Jonathan & C-3PO: when you have BobK sorted out, will you help me make my Bismarck turrets do this?!
 
      YouTube (https://youtu.be/-yEuYGodNLo?t=4s)


Title: Re: Rotating seven gun turrets?
Post by: g6swj on January 12, 2017, 04:34:24 PM
I prefer this

https://www.youtube.com/watch?v=_EAGG9GooE0

 {-)
Title: Re: Rotating seven gun turrets?
Post by: ballastanksian on January 12, 2017, 08:38:32 PM
Beautiful, that takes me right Bach.

Seriously though, would the resonance of the stepper motors cause atonal sounds eminating through the hull? Would it be wise to mount the steppers in vibration damping, say rubber mat to stop Bob's ship sounding odd?

Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on January 12, 2017, 09:52:05 PM
Now this is getting silly (https://youtu.be/G-X-p0C0Uas).  %%


Meanwhile, the steppers are fairly quiet - certainly no worse than servos - but seeing the guitar soundbox/boxy hull connection, it might well be worth mounting them on a rubber mat.


Andy

Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 12, 2017, 10:25:45 PM
In a hull seven foot long I doubt that any servo type noise level will be audible, but mounting on rubber pads is a good idea anyway.

To answer Martin's question re Bismarck, just use the turret routines for A, B, F, and G
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 13, 2017, 11:37:00 AM
I thought it could be fun to give this project/system a name (acronym)

There are some very quick thinking, witty people of this forum - so with some trepidation I invite your suggestions - please keep them clean!

The best I could come up with was WARTS - as in WARship Turret System - feeble really.

So it will be interesting to see other creative suggestions

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Martin [Admin] on January 13, 2017, 12:52:55 PM
 
Sight Handling of Ordnance Turrets = SHoOT

Turret Remote Order Train & Control = TroTac

Remote Electronic Turret Training user Maintained = RETTuM

Modellers Continual Pursuit of the Almost Impossible = McPotaI


Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 13, 2017, 03:48:53 PM
Hard to beat that Martin.

My attempt:  BEATGATOTO    Blooming 'Eck,  Are Those Guns Actually Training On Thier Own ?
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on January 13, 2017, 04:06:27 PM
Ship Hosted Independent Turret Equipment ... hmmm ... Maybe not ideal!  %%
Title: Re: Rotating seven gun turrets?
Post by: Netleyned on January 13, 2017, 04:19:56 PM
Controlled Realistic Armament Positioning


Ned
Title: Re: Rotating seven gun turrets?
Post by: Hellboy Paul on January 13, 2017, 05:21:36 PM
Battleship Universal Turret Trainer..


Turrets Are Really Traversing..
Title: Re: Rotating seven gun turrets?
Post by: Colin Bishop on January 13, 2017, 05:27:45 PM
If anyone asks you what it is called just say 'Arduino?'

Colin
Title: Re: Rotating seven gun turrets?
Post by: Netleyned on January 13, 2017, 05:40:19 PM
Colin,
That's a Cracker :}


Ned
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on January 13, 2017, 06:57:33 PM
Target Acquisition Controller Through Inertial Computation

or, maybe my favorite ...

Turret Training & Tracking Performed Onboard. (T3PO)

Andy



Title: Re: Rotating seven gun turrets?
Post by: ballastanksian on January 13, 2017, 08:22:08 PM
Stepper Powered Automatic Direction Engine

I was trying to create 'POINTY' but could not get a sensible acronym.
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 14, 2017, 09:19:07 AM
Great suggestions -

I thought again maybe TARGET - Turret Active Rotation Guns Enemy Targeting

However I have hit a technical brick wall right now so Ned's description may be more appropriate

Controlled Realistic Armament Positioning

Ned
Title: Re: Rotating seven gun turrets?
Post by: raflaunches on January 14, 2017, 09:43:01 AM
Sorry lads but if you're going to get an acronym for something military it's got to be a TLA!!!


For this not in the know- Three Letter Acronym!!!!




Best five letter acronym I've seen in the military engineering world that I can repeat is SPILs




SPILS (https://www.allacronyms.com/SPILS/Spin_Prevention_Incidence_Limiting_system)
Spin Prevention Incidence Limiting system


When asked why they decided on this the aircrew said 'well it spills my coffee when we go into a spin!'
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 14, 2017, 09:54:28 AM
Nick - not sure the TLA Rules apply to models :)

But if we must - TTT - Turret Turning Technology

Or along the lines that Andy suggested - 3T or  T3

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: warspite on January 14, 2017, 11:01:05 AM
I liked the WARTS as it could be boasted, my boat has warts an all
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 14, 2017, 03:29:16 PM
My technical brick wall is that I seem to have run out of oommphh with the wee beastie.

This got me thinking about the practical installation in a model of stepper motors as each one needs 6 cables connected to it's little driver board  (2 power and 4 motor signal connections)

Even if you mount the Arduino in the middle of a 6 foot model and supply power more locally to the stepper motor that still a lot of cable running inside the hull.

Arduino boards like the Uno ship with lots of goodies on them that most of the time you don't use but as they are often used for prototyping experiments/things it's good to have lots of whistles and bells available.

It's a bit like having a vehicle that's a fire engine, ambulance and police vehicle all in one and you only use it for transporting prisoners back to the nick - all the other stuff doesn't get used.

You can make your own functioning Arduino with just a chip, a resonator and a few simple other components - probably about £5 'ish.

My thoughts are to create an I2C ( simple comms network using 2 wires) network from one MASTER micro controller perhaps the Arduino Mega or Due and then several slaves. The slaves would simply receive instructions from & feedback to the Master and simply control their own stepper - the beauty of this is that an I2C network is made up of just 2 wires. - Sorry for all the waffle

So here is my proposal assuming it can be made to work - it will I think deliver a much easier solution. Picture it this way one controller, a 2 wire network daisy chained to each homemade Aduino controller/stepper motor.

PS an I2C network allows 127 connections or there abouts, you can plug and play in a live circuit etc etc

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: dreadnought72 on January 14, 2017, 05:35:12 PM
Neat solution. For the hull-split Agincourt it'll mean nothing more than a four pin connector at the break? (I2C and stepper power)

My approach with the Arduino Mega means that I'm using just about every I/O pin on the board for six steppers and the inputs, and can see ribbon cables running up and down the boat.

Andy




Title: Re: Rotating seven gun turrets?
Post by: g6swj on January 14, 2017, 06:54:17 PM
Don't you just love the internet - simply Arduino I2C network

http://www.techbitar.com/how-to-network-many-arduinos-with-sensors-using-i2c.html

Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 15, 2017, 12:02:15 PM
Alex (IKB)'s recent post "Arduino and relay control" prompted me to go back to an original thought re moving turrets and a ship of 2 parts.

The I2C network concept is yet to be trialled - I think there may be an issue with TX & RX buffers/ timing of messages - we will see.

If you use a small radio tranceiver per turret like nRF24L01 or RFM69CW there are potentially 2 major benefits - no cables between turrets ( each turret would simply need power)  and the radio TX/RX handles communication traffic as it has it's own buffer all be it small - it does mean the Arduino doesn't have to service comms messages all the time as they are stored on it's own connected TX/RX buffer.

Some testing required to see the best way forward.

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 15, 2017, 03:38:17 PM
This gets ever more interesting.  Anything that reduces an almost Bletchley Park forest of wiring will make it easier (for a non scientist) to build and more reliable.  Not sure how these 2.4 GHz Rx/Tx boards operate in practice.  Do not appear to require "binding".  How does a regular Planet Rx integrate with the system?  Maybe only one Planet Rx per system?  If so, even better for a split hull configuration. No inter-hull wiring at all?  (Optimum solution). 

Each individual turret would be almost a self contained sub system, with just power leads, using a common 2.4GHz local coms network.   Have I got that right?
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 15, 2017, 03:57:57 PM
Bob,

The route I suggest uses RFM69CW 433mhz units. They are separate from any of the radio control TX/RX - The Arduino configures the RFM69CW ( network ID etc)  each time power applied - binding does not apply as such.

So your Planet TX/RX works as normal driving servo's etc - the Master Arduino Controller connects to your Planet RC RX - 2 channels to receive mode(park etc) and direction information, the Master connects wirelessly (433mhz) to slaves.

Pics below show items involved - Pic1 Slave components and size compared to AA battery

In principle this should work well - however until it fires - hold you breath.....

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 15, 2017, 10:37:22 PM
Arduino Master and wireless slave

Initial tests are very encouraging - need to scale the slave network from one device to 7 and see if the wheels fall off.

C-3PO
Title: Re: Rotating seven gun turrets?
Post by: Bob K on January 15, 2017, 10:51:30 PM
C-3PO:  This is looking potentially a realistic A.S.A.D. solution.  Exciting.  If you can build a prototype for, say 4, turrets it will work for seven.  Can I help with donating additional units - in exchange for debugged programs?

PS:  ASAD = All Singing All Dancing.
Title: Re: Rotating seven gun turrets?
Post by: C-3PO on January 15, 2017, 11:28:55 PM
Bob - thanks for the kind offer - I am like a kid in a sweet shop with electronics/Arduino bits. I have enough rfm69's for 1 master and 3 slaves - and I have a few more things in my goody box that I can probably hook up so I think for now I can cobble a system together from what I have. The RFM69CW is my preferred route as it's 433 MHz and not 2.4ghz so should not cause any issues with main RC TX/RX. Without wanting to bore people to death, the bare RFM69 costs something like £4.20 but work using logic pins at 3.3volts - so once it's been mounted on a breakout board with some logic level converters to get it to talk to the outside world at 5volts logic level it costs about £9.60. There may be an option to use an Arduino that works at 3.3volts - I just need to get my head around specs


This concept has now opened up another possibility - the handset control to talk to,the turrets could also be based around a RFM69 TX/RX - so it would be a separate unit perhaps mounted on your Planet TX - this would allow some sexy controls to switch functions control rotation even see real time position of the guns on your control box, fire individual guns - the options / functions only limited by your imagination and of course the technology to make it happen
The mind boggles as to the possibilities - could even be a touchscreen based control unit.......


I will make my code freely available to anybody that wants it when it's finished all I would ask is anybody that uses it makes a donation to the RNLI

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 16, 2017, 07:59:57 AM
Bob,  Have a look at this video - it shows an alternative concept of radio control.

Not suggesting this is used to control the turrets but maybe an idea or 2 could be lifted from the concept

https://youtu.be/4gAW0vQ24z8

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on January 16, 2017, 08:39:23 AM
Impressive.   :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Ian K on January 16, 2017, 05:43:43 PM
Like it, or loath it  :embarrassed:

M-main
A-armamnent
R-rotation
M-might
I-irritate
T-the
E-enemy

Progress on this, is looking very promising!

Ian
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 17, 2017, 10:47:50 PM
A quick update  - I will post a video tomorrow of a turret tracking it's target automatically.

It really is quite cool to watch!

Here is a snapshot of one of the many test beds

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: g6swj on January 19, 2017, 06:54:11 PM
Arduino turret turner spotted....

http://www.modelboatmayhem.co.uk/forum/index.php/topic,57051.msg593260.html#msg593260

Regards
Jonathan
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 19, 2017, 08:49:06 PM
The video below shows live turret tracking - the target is 321 degrees.

https://youtu.be/FFJTJn-q-e4 (https://youtu.be/FFJTJn-q-e4)

Hopefully this gives you an idea of it working - the proximity of the iPhone to my sensor is interfering with things a little - indeed for some reason tonight my iPhone compass is quite jumpy

I made a previous video that was perfect except for one thing - it showed the longitude/latitude on my iPhone screen for the Outer Rim world of Tatooine now covered with the Post It
C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on January 19, 2017, 09:06:19 PM
Very good!  :-))


Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 20, 2017, 08:22:47 AM
Thanks Andy,

I do have some issues that I need to resolve. For example getting the Arduino to read 2 of the RC RX channels presents some challenges.

Using the pulseIn command is very slow( and I am not a fan of this route) , even when you use a timer to read it once every x ms rather than every loop. Using 2 interupts to read the 2 RC RX channels also seems an issue as quite often the RC RX signal out is not stable hence the interupts are on overtime.

Any thoughts?

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Martin [Admin] on January 20, 2017, 08:43:02 AM
 
Can you use two Arduino's?
 They're cheap enough...
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 20, 2017, 09:07:21 AM
Hi Martin,

You may well be right with this suggestion.

I have been working along the lines of KISS - but as you get deeper into the actual development/assessment you find some the the physical limitations that on paper do not present themselves.

I may not of been very clear with my last post, it's all relative, if you are trying to control 7 steppers x 4 digital lines for each (28 signals) , read a sensor, read 2 RC chanels, pat your head and rub your tummy - if just one of these takes more time than you expect it impacts directly on the others as this is not a mutli tasking environment.

I am still wanting to come up with a solution that uses the least amount of kit, is the simplest and cheapest option. I can make most of my development issues go away is I go down the master and slave(s) route but the cost creeps up quite fast....

Not putting pressure on Andy but I know he has taken a different approach and he is writing his own stepper library which may well help with stepper control efficiency.

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Martin [Admin] on January 20, 2017, 11:53:22 AM
 
Keep going C-3PO, we're loving this!   :-))

Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Colin Bishop on January 20, 2017, 01:21:39 PM
Yes, what a wonderful way of staving off dementia!

Colin
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Shipmate60 on January 20, 2017, 05:29:56 PM
Surely the most useful system would be to control 4 turrets as in most capital ships.
The "additional" turrets could be an "add on" for additional turrets.
This would enable more of the systems to be sold and who knows even make a profit for the originators.


Bob
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on January 20, 2017, 08:33:16 PM
I can see the logic of developing the full seven turret arrangement and then developing two, three, four, five and six turret systems from it so that all classes of battleship and cruiser can be controlled.

The originator can release the four turret system as a standard and then later release the other products as and when to maximise on exposure to the market but without the added expense of time and money in development as they have already done it all.

I was wondering if a ten turret system is too way out, as the Warrior class of Armoured cruisers had ten turrets 9.2inch (6x1) and 7.5inch (4x1).

Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on January 20, 2017, 09:01:00 PM
If it helps, my planned build of a seven turret ship will be in two halves.  By all means plan for 4 or 5 turrets, as long as I can put two systems in mine operating from the same Rx channel. 
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on January 20, 2017, 09:21:56 PM
Four turrets (two aft, two forward, both superfiring) is an utter piece... quite straightforward, compared to what's being worked on. (I'm aiming for wing turrets, cross-deck firing solutions, and all the vagaries of WW1 turret layouts).


Getting there!


Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 21, 2017, 10:52:00 AM
Surely the most useful system would be to control 4 turrets as in most capital ships.
The "additional" turrets could be an "add on" for additional turrets.
This would enable more of the systems to be sold and who knows even make a profit for the originators.

Bob

Bob - I cannot talk for anybody else but I have no desire to make this a commercial venture and all the baggage that goes with that (stock, liability etc etc).

My vision is that it's open source, freely available - which would mean anybody can use, amend, add to etc.

I would like to go down the gentleman's agreement that if you choose to use this system - in acknowledgement of the development you make a contribution to the RNLI - perhaps a minimum of £10 - however clearly this is not mandatory.

The core code would be well documented that would hopefully make configuration easy - so if you want 1 or 21 turrets it's easy to make this a reality. I envisage a PDF document that leads you by the hand as to how to buy the kit, put it together and then load the software.

If you Google "Arduino Radio Control" or perhaps have a look at www.rchub.co.uk (http://www.rchub.co.uk) you will see that there are thousands of people playing with Arduino's and RC - most people publish their code openly for others to use.

Arduino's can seem daunting - if you spoke to someone who had never seen an RC kit before and spoke about ESC, Servos, trim tabs, joysticks, servo reverse, reciever channels, proportional control - their head would be spinning with all the jargon which we take for granted. It's the same with Arduino, if you spend a short amount of time getting familiar you wonder what all the hype was about.


I think this video shows that this project is viable, has substance and not just hot air. - https://youtu.be/FFJTJn-q-e4 (https://youtu.be/FFJTJn-q-e4)


Andy (dreadnought72) is also developing a solution, I have not had a conversation with him but perhaps the end solution is a hybrid of both our efforts.

There are few people on Mayhem that have seen the light with Arduino and RC and what it's potential is ( a few are listed below) - have a look at:

Andy's - Turret Control - http://www.modelboatmayhem.co.uk/forum/index.php/topic,56884.msg593347.html#msg593347 (http://www.modelboatmayhem.co.uk/forum/index.php/topic,56884.msg593347.html#msg593347)

IKB's 2.4ghz relay switch http://www.modelboatmayhem.co.uk/forum/index.php/topic,57013.msg592796.html#msg592796 (http://www.modelboatmayhem.co.uk/forum/index.php/topic,57013.msg592796.html#msg592796)

Barriew's ramp control http://www.modelboatmayhem.co.uk/forum/index.php/topic,53368.msg564242.html#msg564242 (http://www.modelboatmayhem.co.uk/forum/index.php/topic,53368.msg564242.html#msg564242)

JohnRedearth's - Ballast Control http://www.modelboatmayhem.co.uk/forum/index.php/topic,54401.msg562802.html#msg562802 (http://www.modelboatmayhem.co.uk/forum/index.php/topic,54401.msg562802.html#msg562802)

Tim - tsenecal - Robbe multi channel decoder http://www.modelboatmayhem.co.uk/forum/index.php/topic,53368.msg557637.html#msg557637 (http://www.modelboatmayhem.co.uk/forum/index.php/topic,53368.msg557637.html#msg557637)

So embrace the little Arduino - it's a lot of fun and very rewarding......

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 22, 2017, 07:22:22 PM
Good news - no technical issues outstanding - previous issue relating to reading 2 rc channels really quickly so it did not slow down the rest of the code now solved - cause was dumb programming

I have been refining my code, making it easier to read, cleaning up stray code and making it run faster and started to document it so it's easily digestible

So I thought I would share with those that are interested the main program loop - this is the code that runs repeatedly after the initialisation (setup code executed etc)

I have put all my code into 7 logical functions that are easy to maintain. This is the main loop code and the functions that are called to be executed - the code itself is stuffed into the functions - none of which are very large or scary!

There is even code for sound, light, smoke and elevation...

Quote

void loop()

{

  read_rc();                          //  read radio control receiver channel A (3 way switch), process and set mode

  read_compass();               //  read mems compass sensor and process

  run_mode_function();       //  run function code associated with mode

  update_turret_limits();     //  update the status for each turret based on movement limits

  update_no_fire_zone();   //  update the status for each turret based on movement limits

  update_steppers();          //  enable stepper, move, disable stepper if reached destination

  debug_print();                 //  run function debug print function - disable by using "//"

}


Regards
C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on January 22, 2017, 10:22:19 PM
Good lord that is so simple! I imagined it being a telephone books worth of typing to realise.

So the functions are extra code beyond what you have published above?
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on January 23, 2017, 09:06:27 AM
Good lord that is so simple! I imagined it being a telephone books worth of typing to realise.

So the functions are extra code beyond what you have published above?


Must be, yes. Each function call is just a swan in the pond - there'll be an awful lot of paddling going on under the surface.


Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Martin [Admin] on January 23, 2017, 01:03:27 PM
 
I've seen 'Beans on toast' recipes longer than that!   :o

 Well done that man!
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 23, 2017, 01:09:12 PM
Good lord that is so simple! I imagined it being a telephone books worth of typing to realise.

So the functions are extra code beyond what you have published above?

Thank you Martin for the compliment....

Re functions...
Yes the main code sits nicely compartmentalised into seperate functions, grouping similar functionality together that get called and executed by the main loop.

Imagine a 500 page reference book without any chapters and no index - this is your program!! - hard to navigate and see what is what.

Add chapters to the book groupling similair functionality together (analogy of functions = chapters) straight away you can use the index ( function name) to jump to the right part of the book (code)

The additional benefit is the main loop is simple and clean and  it's easy to see what is happening in what sequence and to make changes you go to the function  and make changes to the actual code there.

And apart from the waffle above I have to keep it simple so I understand it!

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 27, 2017, 03:57:23 PM
A quick update of C-3PO's version of a solution...

I have been adding code to make the T.A.R.G.E.T system/program more robust.

I have added a "start-up" procedure regarding turret alignment. When the system is switched on an alarm will chirp every x seconds and no turret functionality will work.

The user is required to turn the pot knob on the RC fully to both limits  (could perhaps be another control - but you can't knock the knob like you can a switch!) to confirm the user has placed the turrets in the park position - the system recognises that it has been "calibrated", the alarm is disabled and the system comes on-line.

Should the power be interupted to the unit the above procedure will need to be repeated to get the turrets to move.  A bit cumbersome but better this than bits of superstucture being bashed by turrets.

In all my years of programing I have been caught out many times when the error checking code was not good enough and the unbelievable happened - normally when a variable creeps to an unintended value.

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: roycv on January 27, 2017, 10:14:27 PM
Hi all, still sorting this problem out.  My little grey cells have been at work again.  I have the following 'simple' possible solution.
I am thinking of a different intermediary unit, a cheap servo tester., or actually two  I have a little blue one cost 99p with a knob on for positioning the servo connected. 
I am thinking of drilling a hole through the knob and glueing in a 1mm piece of brass wire.  The end will have a light spring just enough to return it to its extreme right or left position.  So that you turn the knob the servo moves, release the knob the knob returns under spring control.
The main forward gun which trains left or right has a good servo drive.  Now think of this as the tiller with two arms and rods.

When the main gun servo turns say left it will push the extended wire of servo tester which is connected to the left side guns and they will move from ahead to broadsides.  The rod operating the servo tester will have short tube attached where the spring is located so it is a bit like a piston in a cylinder.  The rod from the 'tiller' arm (main forward gun) will push the whole tube as there will be a collar on the rod and the servo tester turns and operates connected servos.

When the forward gun points ahead again the rod will stay in the tube (cylinder) but the spring will return it until the left side guns train ahead.  When the main gun trains to the right the rod will be retained in the cylinder but have no effect on the servo tester movement.

There will be a second servo tester for the right hand side with a similar connection.
So when the guns train left or right only one servo tester will operate.  My little blue servo tester has 3 o/p servo connections and requires its own 5 volt input.
Cost of this is less than a fiver and no programming, anyone see any flaws in the idea?

My little grey cells are now exhausted!
best regards Roy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 29, 2017, 09:41:14 AM
REFERENCING A TARGET

How do you refer to a target? Do you simply always use the magnetic compass point?

In my head I can hear phrases like Green 050 - not sure if this fact, fiction or Hollywood. Clearly if you are on a boat without a compass then using the port/startboard 180 arc is meaninful.

Maybe some of relates to aircraft?

So can someone out their put me out of my confusion.

On a navy ship what reference would you use for a target?

Cheers
C-3PO

PS - roycv - your idea sounds very creative - will be interesting to see if you can make it reality - will follow with interest.....
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Allnightin on January 29, 2017, 10:33:13 AM

So can someone out their put me out of my confusion.

On a navy ship what reference would you use for a target?


In a modern ship with a radar based command and control system it would be something like " Take track 1234 with 4.5" (and no mention of true or relative range or bearing) unless  caught by surprise and the first indication was a visual sighting from the Gun Direction platform on the upper deck when the call might be "Alarm aircraft Red 90"
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Colin Bishop on January 29, 2017, 10:49:05 AM
You mean it's not just 'look over there!'?  ok2

Colin
Title: T.A.R.G.E.T. - Rotating seven gun turrets?
Post by: C-3PO on January 30, 2017, 10:58:53 AM

1:   training +/- 150 ‘.  No firing, directly ahead, say +/- 20’, and beyond +/- 140’
2:   training  +/- 150’.  No firing over hood below +/- 30’, and beyond +/- 140’.
3:  training between 25’ and 150’ either side.  No firing 10’ inside this either side.
4:  training between 30’ and 150’ either side.  No firing 10’ inside this either side.
5:  training between 25’ and 150’ either side.  No firing 10’ inside this either side
6:  training  +/- 150’.  No firing over hood below +/- 30’, and beyond +/- 140’.
7:  training +/- 150 ‘.  No firing, directly astern, say +/- 20’, and beyond +/- 140’

Using Bob's information above I have a few questions on what the expected behaviour of turrets 3,4,5

I have the question in my head - let's hope I can explain it in text:(

Scenario A

From Park - If using the pot I move the position of T1 to 45' (forget turret 2,6,7 for now)  I would expect T3,4&5 to join in the same position.

From Park  - If using the pot I move the position of T1 to 10' what happens to T3,4&5 as they can only track to 25' or 30' - Do I move them to their lowest degree track position so they are as close to T1 as possible or something else.

Rather than make this post more complicated I will only pose one scenario at a time as the solution to one scenario may answer other questions I have.

Thanks in advance
Regards
C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on January 30, 2017, 11:30:00 AM
Not sure if I have fully understood this one.

However, a turret that CAN bear on its designated target should do so.
Other turrets that can not quite reach this angle should bear as close as their limits allow, in case the ships heading alters later so that they can bear.  If a wing turret that cannot fire across the deck finds itself on the "wrong side" of the ship it should revert to parked position until the target moves to its own firing side.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on January 30, 2017, 11:36:41 AM
Bob,

Thank you

Got it So if T1 @ 20' T3,T4&T5 would go to 25',30',25' as close as they can get to 20' of T1

So  using pot T1 now goes to 340' you would expect T3,T4,T5 to go to  335,330,335 ?

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on January 30, 2017, 04:10:03 PM
However, a turret that CAN bear on its designated target should do so.
Other turrets that can not quite reach this angle should bear as close as their limits allow, in case the ships heading alters later so that they can bear.  If a wing turret that cannot fire across the deck finds itself on the "wrong side" of the ship it should revert to parked position until the target moves to its own firing side.


That's the solution I'm adopting. "Can't fire? Go to the nearest firing arc limit."


Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on February 01, 2017, 09:45:28 PM
I made this video a couple of weeks back, thought I would post it now to keep the thread warm as for some reason my video camera doesn't want to recognise a memory card so my video exploits have come to an abrupt halt!

https://youtu.be/uWYJ2W-5K7k

Using the pot control on the RC TX you can see the how the turrets rotate.

When I unravel issues with camera I will update you with my latest...

Regards

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on February 01, 2017, 09:50:47 PM
Seeing that and imagining those to be turrets. Any battleship so equipped is going to look amazing :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on February 01, 2017, 09:56:13 PM
When warships equipped with this system start patrolling the numerous club lakes and shows everyone is going to want to upgrade.  Just think of a WW1 fleet in line of battle, all training on the same target !
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Colin Bishop on February 01, 2017, 10:06:38 PM
Wow!

Colin
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: raflaunches on February 01, 2017, 10:16:32 PM
Now that is impressive! :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on February 01, 2017, 10:35:30 PM
When warships equipped with this system start patrolling the numerous club lakes and shows everyone is going to want to upgrade.  Just think of a WW1 fleet in line of battle, all training on the same target !

The idea is making me warm and fuzzy inside Bob.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on February 01, 2017, 10:48:33 PM
Lovely - looks like you're nearly there!


I'm currently turning 'flowcharts' into 'code'. The job gets in the way, though - doing a mad 50hrs/week atm - so I'm now aiming for (see what I did there?) mid-February. I'd love to 'compare notes' at that time.


My video to follow!


Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on February 08, 2017, 09:09:47 AM
Hi Guys,

Another query from me - when the guns are fired how did different turrets fire - was the fire command communicated electrically so they all fired together, by voice comms so a human pressed the fire button so slight variance in fire execution, or something else?

Or should I be incorporating a configuration option to fire with small random delay or exactly at the same time?

The reason for asking is I am finalising the "Gun Fire" aspect of the application and wanted to understand if there should be a fractional delay between each turret firing ( assuming that it's not in the NFZ) or do they fire exactly at the same time

Thanks in advance

PS Has anybody used these as a heater for gun smoke? - I played with these last night in my utility room - lots of smoke - just as well my wife was away on business!

3D printer heating element -
http://www.ebay.co.uk/itm/like/221425111395?lpid=122&chn=ps&adgroupid=33676502101&rlsatarget=pla-270397383003&adtype=pla&poi=&googleloc=9046187&device=c&campaignid=707291931&crdt=0 (http://www.ebay.co.uk/itm/like/221425111395?lpid=122&chn=ps&adgroupid=33676502101&rlsatarget=pla-270397383003&adtype=pla&poi=&googleloc=9046187&device=c&campaignid=707291931&crdt=0)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on February 08, 2017, 09:40:49 AM
As far as I understand, the overall command to fire was given by voice pipe and someone in the turret pressed the fire button, so a slight variable delay might have been involved, but not much.  Setting the gun elevation for the range allowed for firing at the top of the roll, which was better observable from the control top rather than from inside the turret.  There must have been feedback from each turret when "ready to fire", so the control top had to take that into account. 

I will check out your 3D printer heater link.  Could be useful  :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Colin Bishop on February 08, 2017, 05:43:28 PM
I think the answer very much depends on what ship you are depicting and at what stage of the war as continual improvements were made in fire control arrangements as ships came in for refit. Towards the end of the war I think that most, if not all,  capital ships of the Grand Fleet would have been fitted so as to allow the gunnery team in the director to actually fire the guns.

The information is out there if you have the time to look for it!

Colin
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on February 08, 2017, 06:20:27 PM
Hi Guys,

Another query from me - when the guns are fired how did different turrets fire - was the fire command communicated electrically so they all fired together, by voice comms so a human pressed the fire button so slight variance in fire execution, or something else?

Or should I be incorporating a configuration option to fire with small random delay or exactly at the same time?

C-3PO

I will make it configurable then hopefully it will work in most situations...

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: raflaunches on February 08, 2017, 06:50:20 PM
Just fetched out my copy of Dreadnought Gunnery and The Battle of Jutland The Question of Fire Control by John Brooks, it's a heavy read but I have found out the following about fire control in Dreadnought type battleships:


By 1906, the supply of almost all the fire control instruments for Dreadnought had been arranged. However, after successful experiments aboard Duke of Edinburgh, it was decided that, in future, the clocks and range and deflection transmitters to the individual turrets should be moved below to a transmitting station (TS), protected by armour, near the base of each mast.  The TS would be connected by a large voice pipe to its top, where the range finder and Dumaresq remained, 'the initial range and spotting corrections and deflection' being passed by voice popes and the 'rate' by special electrical transmitters.


In the TS of the first Dreadnoughts , a clock operator would 'call the 25s and also call the range every time a full hundred yards is reached' while the transmitter men (one per turret) would rotate the transmitter handles at each 25-yard step. At the guns, the sight-setters then had to read the ranges and deflections off the receivers and set the sights accordingly, although, by 1909, they had provided with telephone headsets, through which they hear the range steps being called in from the TS.




As I said it's a complicated book and I'll scan through it to find further information  :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on February 09, 2017, 12:06:18 AM
Always good for a one-stop shop is the Dreadnought Project's page on fire control (http://www.dreadnoughtproject.org/tfs/index.php/Category:Fire_Control#See_Also).


The information under Spotting Rules is good for the post-Jutland era: salvos of 'three or more guns' in an attempt to straddle, double salvos to help precisely define the position of the enemy, and then director firing of, basically, any gun that's loaded to maximise the fall of shot and minimise the 'wait' time for a loaded gun.


...and all that seems to infer that a gunnery officer is doing the physical trigger-pulling for any mix of available weapons.


Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on February 09, 2017, 12:17:58 AM
And special mention should be made for the 'Usborne Fall of Shot Indicator'.


Steampunk at its best.  :-))


A slowly rotating drum with a helical track in it receives a ball bearing as a gun is fired. The ball bearing moves along the track to a point where it meets a switch which forces a buzzer to sound. The switch's position is adjusted for range and hence the expected time-of-flight for that salvo. In effect, as the ball bearing travels a few inches, and the shells a few thousand yards, the spotters get an audible cue for when their shells should be striking the target.


Got to love this kind of ancient mechanical technology.  %%


Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Martin [Admin] on February 09, 2017, 02:05:27 AM

And special mention should be made for the 'Usborne Fall of Shot Indicator'.


http://dreadnoughtproject.org/tfs/index.php/Mechanical_Aid-to-Spotter_Mark_I
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on February 09, 2017, 09:28:49 AM
And special mention should be made for the 'Usborne Fall of Shot Indicator'.


Steampunk at its best.  :-))


A slowly rotating drum with a helical track in it receives a ball bearing as a gun is fired. The ball bearing moves along the track to a point where it meets a switch which forces a buzzer to sound. The switch's position is adjusted for range and hence the expected time-of-flight for that salvo. In effect, as the ball bearing travels a few inches, and the shells a few thousand yards, the spotters get an audible cue for when their shells should be striking the target.


Got to love this kind of ancient mechanical technology.  %%


Andy

Your description of this overly complex mechanism, plus descriptions of the Dreyer Fire Control Table which required nine operators, gives me the increasing suspicion of evidence of the design handiwork of Frederick Rowland Emett.  That ball bearing and buzzer is a dead give away. 

It may also be true that at the heart of the Type 45 fire control system lies a single Arduino ?
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on February 09, 2017, 11:05:37 AM
Anybody got any good sound files of a large gun firing ( ideally just a single gun)  or can point me in the direction on the net where they can be found?

Also what is happening when these guns move down after firing - is it some of the recoil?

https://www.youtube.com/watch?v=dVvEPTYrcXA (https://www.youtube.com/watch?v=dVvEPTYrcXA)


C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Colin Bishop on February 09, 2017, 11:31:02 AM
The gun should recoil and then run back out again as it drops to the loading angle.

Colin
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: RAAArtyGunner on February 10, 2017, 12:43:13 AM
Anybody got any good sound files of a large gun firing ( ideally just a single gun)  or can point me in the direction on the net where they can be found?

Also what is happening when these guns move down after firing - is it some of the recoil?

https://www.youtube.com/watch?v=dVvEPTYrcXA (https://www.youtube.com/watch?v=dVvEPTYrcXA)


C-3PO

Yes, the larger the calibre the greater the "whip" is, proportional to the charge used. Think of it as you fire a rifle, if you don't hold it firmly it "flies up the down".

Larger charges produce "faster" recoil, runout. All normal ballistics.

You will note in the clip the last charge bag is kept separate from the first three bags and "rammed" with the next three charge bags, total charge six bags.

Because these are Breech loaders, (BL) meaning no cartridge case is used, not that it is loaded from the breech, when the gun recoils the breech does not automatically open to eject the cartridge case.

Once the recoil forces have ceased, happens quickly but visible, the gun "returns" ready for reloading.

Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on March 04, 2017, 01:14:13 PM
Hi

As with most projects life gets in the way.

This is a video of where I was some weeks ago when my video camera decided not to play ball.

Hopefully it gives you an idea of where I have got to...

AUDIO CONTENT - Make sure you have audio enabled...

https://youtu.be/qi1yiM26eAM (https://youtu.be/qi1yiM26eAM)

Notes

3 of the turrets in the Gun Fire shot decided to disconnect (operators fault)
The Gun fire clip is for demonstration only - it shows each flash and audio in under independent control - clearly the sequence does not reflect real life

So there you have - that's all folks until the next exciting episode

Regards

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on March 04, 2017, 10:15:36 PM
Real or not, the fact is the system you have developed is pretty much there. We will never be able to recreate gun fire and control completely, but this looks like it will meet most users requirements.

Good one C3PO  :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on March 05, 2017, 10:50:30 AM
Sound files - can anybody point me in the direction of sound files of large guns firing? ( downloadable would be great) but if decent quality then happy to purchase...

Thank in advance
C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on March 05, 2017, 11:04:49 AM
Several YouTube videos of big guns firing.  This one is from USS Wisconsin.
https://www.youtube.com/watch?v=dVvEPTYrcXA (https://www.youtube.com/watch?v=dVvEPTYrcXA)

Individual guns are firing in 1-2-3 sequence.  Suggest use a good sound editor to capture the first gun in a sequence, shorten it to omit the end (before start of second gun), then append the end of the third gun firing.
Might need a bit of trial and error but the overlap is not too critical.

For purely sound files you are limited to much smaller calibres from what I can find.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: RAAArtyGunner on March 05, 2017, 11:53:05 AM
Several YouTube videos of big guns firing.  This one is from USS Wisconsin.
https://www.youtube.com/watch?v=dVvEPTYrcXA (https://www.youtube.com/watch?v=dVvEPTYrcXA)

Individual guns are firing in 1-2-3 sequence.  Suggest use a good sound editor to capture the first gun in a sequence, shorten it to omit the end (before start of second gun), then append the end of the third gun firing.
Might need a bit of trial and error but the overlap is not too critical.

For purely sound files you are limited to much smaller calibres from what I can find.

Bob,
That is the same youtube C-3PO referred to in his post 291???
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on April 08, 2017, 01:23:55 PM
Bob,

At the scale you propose to build this ship (HMS Agincourt?)  what would be the calibre (scale units)  of the large guns?

Would I be correct that they where 12" guns which by my reckoning would be 0.125" @ 1:96

Thanks in advance

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: raflaunches on April 08, 2017, 01:30:11 PM
Hi C-3PO


I think that sounds right as 1/8" of an inch equals 12inches in 1/96 scale :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on April 08, 2017, 01:40:46 PM
Hi Nick,

Thanks for the confirmation - I need to be more creative to get the size down of the goodies I am working on...
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on April 08, 2017, 01:58:10 PM
Just picked up on your question C-3PO.   yes 1/8 inch at 1/96 scale.
At a pinch I could go up to 4 mm by having thinner barrels.  What do you have in mind?
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on April 08, 2017, 03:48:00 PM
Hi Bob,

Keeping my matches dry for now but I do have one more question.

It looks from the crude measurement I made below that in this image the diameter of the gun barrel looks approx twice that of the calibre.

So 12" calibre approximates to about 24" diameter barrel - is my logic sound? and at scale OD of barrel approx 1/4inch?

Please note the screen ruler is using centimetres just because it was easy as the 8 cm mark aligned nicely ...

Thank you for your help

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on April 08, 2017, 04:35:36 PM
Sorry C-3PO, I am stumped on that one.  Outside diameter does vary along the length though. 
At the muzzle 2 x i/Dia sounds about right

I always thought a gun of 12 inches was a measurement taken from the Shipwrights model, as to how much of it stuck out of the turret?   %%
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Colin Bishop on April 08, 2017, 05:35:37 PM
Check out this link - it has a constructional drawing of a 12 inch gun of approx the right vintage:

https://commons.wikimedia.org/wiki/File:BL_12_inch_Mk_VIII_gun_diagram_Brasseys_1899.jpg (https://commons.wikimedia.org/wiki/File:BL_12_inch_Mk_VIII_gun_diagram_Brasseys_1899.jpg)

Click on the gun image for a larger view.

Colin
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on April 08, 2017, 10:28:06 PM
Most British guns, and those inspired by our guns had a bell muzzle which neatly curved out of the taper gently to the muzzle. Other nations either had the taper straight to the muzzle or had a squared collar which looks awful in my opinion.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Geoff on May 12, 2017, 02:29:10 PM
I may be joining this debate a little last so apologies if this idea has already been suggested. On my Iron Duke I have five turrets and I linked all the aft facing ones together using mono filament fishing line as each sits on a drum. The drums are then winched round using a servo sized drum sail winch. The same for the forward turrets with a separate winch. With modern radio equipment you can control both the speed of rotation and the throw at each side. I control both groups separately (I have potentiometer pots to use on my system). Because the pull is on the circumference of each turret rotation is very smooth.


With Agincourt you could do the same which would mean all the forward facing turrets could turn to any position you want and if abaft the beam the aft turrets could be controlled to point in the same direction.


Absolute parallelism isn't needed on the pond because at any distance you just can't see that accurately. Because the groups are separately controlled I can fine adjust them for the centre line. I think an Arduino based system is probably the gold standard but this system works well enough and is easy to construct and maintain.


Hope this may be of help


Cheers


Geoff
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 13, 2017, 11:18:33 AM
Hi Geoff,

The thread developed from the basic moving of turrets to something more ( see the detail in the posts) - Lots of "whistles and bells" functionality was added to the basic movement solution which perhaps pushed it in the direction of what might be considered the gold standard.

The movement of turrets only using stepper motors controlled with an Adruino compared to your solution would be comparing apples with apples

So I would suggest that the Arduino/stepper route is a quick and easy way to achieve the outcome without investing time and effort in R&D and fine tuning of the engineered solution to get it to do what you want.

In my simple world placing 7 steppers motors into holes cut in the deck, ( very similar to mounting 7 servos) supplying each with power and a data signal , plugging these into an Arduino which in turn is connected to the receiver seems more simple than to devise and install a turret mount and pulley system and all that entails to control multiple turrets.

I think the stepper motor route is like a "pre-made solution" and you just install components and connect them together where as your route is the "Scratch Build" route which for many of us is the more challenging route as in essence you start with a blank piece of paper and have to go through the same learning curve you experienced with any "funnies" to iron them out - How create a mount, , pullies, cord,  what amount of friction vs. slippage etc

Just my 2 pence worth - the good thing is  people have a choice and should they wish to "move their turrets" could use either of of the 2 routes or make their own hybrid - they simply have to choose which they think is easier to construct and the functionality they desire.

To enable others to use the stepper route if they want to - it is the intention to publish a "How to guide" at some point in the future which would detail all that's involved, the code , the components and you simply choose what functionality you want from basic movement of a turret through to target tracking, synchronised sound/light/smoke/gun recoil

Bob's HMS Agincourt build thread will give more detail as things progress - http://www.modelboatmayhem.co.uk/forum/index.php/topic,58070.msg605416.html#msg605416

Regards
C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on October 17, 2017, 10:23:16 AM
Update - as the season's change more time indoors to play boat bits...

Behind the scenes things have been ticking over slowly.

To make this solution work for Bob K’s HMS Agincourt ( “ a boat of 2 halves”) a method was needed to communicate with the turrets in each half of the hull.

Bob was certain that he did not want any cable connections between each part of the hull so another solution was needed.

So a re-think of how this could be achieved has yielded some significant, initially unforeseen benefits to the whole solution…

Rather than having one Arduino with loads of pin connections (Ardunio Mega 2560) a more simple route has been adopted using one Arduino Uno as a Master Controller and the very small Ardunio Nanos (Approx £3 each), one for each “Turret Control Unit”

The “Master” controller reads the RC Receiver signals and the Compass sensor and then sends commands along with the Turret Heading to each “Turret Control Unit” wirelessly on 459Mhz

This does away with the cable looms running up and down inside the hull as each “Turret Control Unit” simply needs a 2 wire power supply connection.

The added benefit for this system architecture is that we now have a local processor at each turret that can be used to implement “Auto Alignment” of the stepper motors at system startup. Using an IR sensor for alignment, an accuracy of 1 degree can be achieved. It would also be possible for the IR sensor to act as a watchdog to limit the turret movement to a predefined range.

So each “Turret Control Unit” is made up of – Arduino Nano / Stepper motor and control board / 459mhz Radio Transceiver / Relay for triggering smoke generator / LED control for gun flash

Regards
C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on October 17, 2017, 11:40:39 AM
Many thanks C-3PO.  It might sound more complicated, but having a universal sub-assembly for each turret actually makes interconnection wiring vastly simpler.  Each 'local' electronics unit can be individually customised to suit physical bearing angle ranges etc (I think).

Meanwhile the 7 foot ship is coming along.  Just fitted the four motors shafts and "A" frames.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on October 17, 2017, 06:54:28 PM
The added benefit for this system architecture is that we now have a local processor at each turret that can be used to implement “Auto Alignment” of the stepper motors at system startup. Using an IR sensor for alignment, an accuracy of 1 degree can be achieved. It would also be possible for the IR sensor to act as a watchdog to limit the turret movement to a predefined range.


Now that's a good idea. I'm currently using the thirty seconds of 'compass output settling time' after start-up to run through a manual turret alignment sequence. (But I'd sooner watch turrets sort themselves out!)

Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on October 21, 2017, 05:41:39 PM
I have been playing with creating an "Auto Align" sequence for the little stepper motors.

The current thinking is to use an IR sensor to achieve the alignment. The IR Sensor has the "IR Source" and "IR Sensor" facing each other and the Arduino can sense if the IR beam is broken/made by reading the sensor.

My jaw has dropped a little as I didn't expect is to be so accurate. My latest test is using a scalpel blade cut as the "slot" that allows the IR source to pass through to the sensor. I guess due to the very small wavelength of the IR  the slot appears to be a mile wide!

For test purpose a slot cut in a piece of stiff paper is fine - but can anybody suggest how to source/create a very small slot in a more durable material for use in a model boat. For size comparison you can only just see light through the paper cut I am using now when held up to a bright light source.

Thanks in advance for any suggestions

Regards
C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on October 21, 2017, 08:15:33 PM
If I am imagining correctly the IR unit as a "U" shaped slot in a block, then the beam probably has a relatively large diameter.  Maybe 3 mm ?  Any way to reduce this with a mask so the beam is smaller?
Alternatively instead of a cut would some stretched fuse wire over a slot provide a trigger point?
Or very thin brass, photo-etched?  ie:  A section of steps (flat) and just opening one tread by a few degrees.

Just some thoughts.

Bob K
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on October 22, 2017, 09:53:41 AM
Hi Bob,

Fascinating little device. The sensor already has a slot - just over 1 mm wide. It doesn't seem to use the whole slot just the part highlighted with the red line.

The sensor trigger can be made by either making or breaking the beam.

I have changed my approach a little as I want the implementation to be simple and reproducible with out much tinkering.

Current logic is to have a wider slot window on the component that passes through the sensor and capture the stepper motor step that the sensor is "triggered on" and the same when "triggered off" and compute a mid way between these 2 positions as the alignment "step".

I also have some Hall effect sensors on order as well as some very small magnets to see if this approach has any merits ( Magnets -  5MM X 2MM ,3MM X 2MM , 2MM X 1MM )

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on October 25, 2017, 11:30:32 PM
Well having gone down a few dead ends I now have a working solution for aligning stepper motors as they are powered on.

Unlike servos they have no inbuilt position feedback mechanism (internal pot)

The accuracy is stunning - certainly less than 1 degree

Just a little bit of code to write and the process will be automated.

I will post a video once it's completely finished.

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on November 01, 2017, 09:21:51 PM
Video showing stepper motor auto alignment.  Each cycle the power is reset and at start-up we have no idea of the relative stepper motor position.

Interesting experiment... Youtube video link https://youtu.be/e1lEdoixKfI

C-3PO

(http://www.rchub.co.uk/images/stepperautoalign1.jpg)


(http://www.rchub.co.uk/images/stepperautoalign2.jpg)
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on November 01, 2017, 11:21:17 PM
VERY neat.  :-))  I'm guessing that accuracy with Hall effect sensors won't be nearly so precise - but those would be good with tasks such a multiple revolution counts (winches, propshafts, etc.)


Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on November 02, 2017, 01:14:51 AM
Impressive  :-))  It looks like you have solved the start up position issue. 
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on November 02, 2017, 05:03:21 PM
Hi Andy,

I think the sensor would work very well for 
Quote
but those would be good with tasks such a multiple revolution counts (winches, propshafts, etc.)

Another application for the little beast - https://www.youtube.com/watch?v=cxpSbWlj8FQ

The solution uses one of these - TCRT5000-INFRA-RED-SENSOR – simply point at the surface at a distance of 15mm'ish

No driver required – simple 3 pin connection – even got an LED on the board that indicates sensor triggered so you can play around with it to see how it senses without the Arduino.

I am using black and white electrical tape as the surface that the sensor looks at – really simple stuff….

It took me a little time to get my head around why I got different trigger points depending on direction of travel. My conclusion it that as the emitter is to one side of the sensor and the receiver the other in relation to the direction of travel – so I guess it’s no surprise that for the emitter to shine it’s thing where the surface changes colour (black to white or white to black trigger point) they will be different depending on direction of travel.

The above explains why you see my alignment sweeps backwards and forwards

The trigger line is monitored by the Arduino using a “hardware interrupt”

Available from here - https://www.ebay.co.uk/itm/2x-TCRT5000-INFRA-RED-SENSOR-LINE-TRACKER-FOLLOWER-ROBOTS-ARDUINO-PI-UK/272910818377?hash=item3f8ac09c49:g:ukAAAOSw44BYmNFl (https://www.ebay.co.uk/itm/2x-TCRT5000-INFRA-RED-SENSOR-LINE-TRACKER-FOLLOWER-ROBOTS-ARDUINO-PI-UK/272910818377?hash=item3f8ac09c49:g:ukAAAOSw44BYmNFl)

(http://www.rchub.co.uk/images/TCRT5000.jpg)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on November 30, 2017, 05:08:38 PM
Smokin...

My version of smoke generation - basics working - now need to refine it and make it useful

https://www.youtube.com/watch?v=i43oJEIi6hY


(http://modelboatmayhemimages.co.uk/images/2017/11/30/Smokin.jpg)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: bfgstew on December 01, 2017, 10:09:42 AM
I have not read the whole thread so I apologise in advance if I go over old ground.
My dealings with steppers and micros (picaxe) is fairly good and have some very good, accurate results with a camera macro stack driver and cnc router. The main point being is counting, as long as it is told to count each step it can go back to the exact same start point every time, no need for IR sensors or any other added input devices, which can cause errors, it can all be done with coding.
Sorry if trying to teach granny to suck eggs.


Stewart
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on December 01, 2017, 10:53:13 AM
Hi Stewart,

I love eggs :)

The issue is simply that the stepper mounted in a model boat, powered by batteries ( that go flat!), interfaced to RC kit, no clever system to keep the power on while steppers automatically return to home as the user removes the power, shoved in and out the back of a car is going to lead to the stepper ( or the turret mounted to the stepper with fit that allows some rotation! covered else where in thread ) not being in it's known "Home" position at some point when you power up the system.

This was clearly not an acceptable situation.

So obvious route was to have a manual alignment process/confirmation at power on to confirm steppers (turrets) in known "Home" position to prevent the possibility of gun turrets rotating into parts of the superstructure. One option was to have a slip friction fit of the turrets so you simply rotated them on the stationary stepper to align them - bingo..

All this lead onto a way of automating the process - the IR sensor.

Agree 100% - in the ideal world if all the steppers where located in "home" position at power up none of this waffle would be required... but what do you do if they are not?

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: bfgstew on December 01, 2017, 11:13:18 AM
C3PO...........i agree in principle with your dilema and it is frustrating that making things fool proof is somewhat tiresome (not saying you are a fool by a long stretch), and raises more complications than it solves, (been there, done it).
My macro stack unit, i can get it to do any amount of steps in any amount of configurations, press home button it goes back to its home position. Powered off a 12v wallwart power supply. Same with my cnc, always goes back to home. Now as long as the units are not disturbed everthing is hunky dory. This is the problem. Then, what I would do would be to have 2 sets of reed switches set at either end of travel, on start up/power on, simple routine to run each turret to one switch then opposite direction to the other, counting steps as it goes, divide the longest travel, divide by 2 and that will be home. Use very small magnetic reed switches rather than opto switches as water can play havoc with opto stuff.
Again i apologise if this has been covered, when i get time i will go through the whold thread as this is very interesting.

Stewart


Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on December 01, 2017, 11:40:25 AM
Hi Stewart,

No apologies needed - if there is a way to enhance this then I am all for it....

My own experience of micro reed switches is I got varying trigger points so I discarded this as an option for this project. Maybe the quality of the components/magnets etc where not good ( or more likely the implementation by the user (me) was suspect)  - I may well revisit this.

Points noted re the water - chances are if the sensors are wet then so is a lot of other electronics!

I guess this is one for Bob to consider as I am just playing with this topic - the Mug Mayhemer who is likely to install it for it's maiden outing is Bob K in his magnificent HMS Agnincourt build.

I am currently focusing on producing lots of smoke on demand for 14 guns in 7 turrets from one central smoke unit not using 12v SLA's

All part of the fun...

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: bfgstew on December 01, 2017, 11:55:56 AM
Been following BobK's Agincourt build.......what a beast.
Would love to do a large scale Hood or KGV myself so have a slight vested intrest in this.
Will get the old thinking cap on while i am decorating my mother in laws spare room this afternoon.... :-))


Stewart
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on December 01, 2017, 12:35:08 PM
Will get the old thinking cap on while i am decorating my mother in laws spare room this afternoon.... :-))
Stewart

Stewart,

It's the only reason I got involved - to stimulate the grey matter - I often find myself turning over a problem in my head seeking a solution whilst doing the mundane things - so I am now off to fit 3 radiators - great joy...

Re the smoke - I know Geoff has come up with a great solution on his build - just seeing if I can get more smoke without loads of batteries...

So far so good but testing in its early stages

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on December 01, 2017, 12:38:35 PM
Stewart:  it is indeed !   Am I crazy?  Quite probably.  By all be tempted into a giant 1/96 warship.   %%

C-3PO has kindly been giving me technical assistance on controlling turret rotation for all seven turrets.  I will defer to his electronics/Arduino expertise in developing the technology for this.  I believe it will look really amazing on the water, something of a model boating first.  Once operational I am sure others will then want one.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: bfgstew on December 01, 2017, 06:48:57 PM
Can I ask how the turrets are to be controlled? Is it going to be as simple as flick a switch and the turrets will dance a tune pre-programmed, then return to home position, of several switches with differing programmes? Or a custom control deck with pots for each turret, turn the pot, the turret turns.


I like the idea of the custom deck..........really got the grey matter going now.


Stewart
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on December 01, 2017, 07:04:11 PM
Stewart:  C-3PO's system uses an electronic compass to find due north.  You rotate a knob on your transmitter to set the desired bearing angle, and any guns that can train on it will do so.  The clever bit is when your ship changes course the guns will continue to bear on that target, provided they can train onto it.  Natty  O0

Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: richald on December 01, 2017, 07:05:51 PM
Can I ask how the turrets are to be controlled? Is it going to be as simple as flick a switch and the turrets will dance a tune pre-programmed, then return to home position, of several switches with differing programmes? Or a custom control deck with pots for each turret, turn the pot, the turret turns.

I like the idea of the custom deck..........really got the grey matter going now.

Eight people sat pond-side, seven with their own turret control box, eighth as fire control officer, passing them (electronically) targetting and fire instructions! %%

Richard
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Colin Bishop on December 01, 2017, 07:07:12 PM
I don't build warship models but am still very interested in this period of naval history.

I think that the hardware/software solution that has been arrived at for model use is a huge leap forward in achieving realism. Well done!

Colin
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: bfgstew on December 01, 2017, 07:09:53 PM
Now that is one sweet piece of kit.
Going to tag along on this, very very interesting.... :-))


Stewart
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on December 02, 2017, 08:23:11 AM
Or a custom control deck with pots for each turret, turn the pot, the turret turns.

I like the idea of the custom deck..........really got the grey matter going now.

Stewart

Hi Stewart,

Custom Deck - This might interest you - https://youtu.be/4gAW0vQ24z8


http://www.modelboatmayhem.co.uk/forum/index.php/topic,56800.msg592985.html#msg592985 (http://www.modelboatmayhem.co.uk/forum/index.php/topic,56800.msg592985.html#msg592985)

C-3PO

(http://modelboatmayhemimages.co.uk/images/2017/12/02/Fletcher_RC.jpg)
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on December 02, 2017, 11:05:07 AM
Smoke Generation - proof of concept #2

https://www.youtube.com/watch?v=xXExgFkZVxM

C-3PO


(http://modelboatmayhemimages.co.uk/images/2017/12/02/TargetSmoke2.jpg)
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: bfgstew on December 02, 2017, 03:07:59 PM
Now that is some serious gear.
Lots of work going into this, doff my cap to you sirs.


Not ventured down the Arduino route, stayed with Picaxe, the language is slightly easier to work with for me anyway.


A normal capital ship with 4 turrets will be slightly easier to manage rather than the 7 on BobK's leviathan.


Are you going to have some sort of valve arrangement on each barrel to simulate firing and then breach opening. It always makes me chuckle when you see these big guns hurl out massive projectiles with a huge bang and a mass of flames and when the breach is opened this whisp of smoke comes out the end of the barrel like in the old westerns with the old six shooters.


Stewart
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on December 02, 2017, 03:46:34 PM
Stewart:  Getting 4 or 7 turrets turning, the only difference is in repeating the small electronics board and stepper for each.

The actual gun fire system will be based on Geoff's awesome Iron Duke model.  A small piston pushes a measured quantity of smoke fluid up through a Thermistor heating block inside the turret.  Very effective.  (photo: (c) Martin MBM).

(https://photos.smugmug.com/General/i-FK8N2zZ/0/41433f63/M/Iron-Duke-M.jpg) (https://bobkiralfy.smugmug.com/General/i-FK8N2zZ/A)

On the actual ship, after firing, compressed air was blown up the barrel, so only a very small amount was visible when opening the breach.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on December 10, 2017, 04:42:15 PM
Ooops
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on March 04, 2018, 11:26:22 PM
After many iterations it looks like this will be the version that gets built for real for Bob K's HMS Agincourt- 11 microprocessors in all

(http://modelboatmayhemimages.co.uk/images/2018/03/04/TARGET_101.jpg)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Martin [Admin] on March 04, 2018, 11:50:07 PM
 
I think that  probably has more  functionality than the whole of the original ship, officers & crew!   :o
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on March 05, 2018, 07:39:05 AM
I greatly appreciate your development work on this.  The overall effect will look awesome  O0

It seems you have been able to greatly simplify the system workings.  One module per turret + MCU master and slave.  Audio units a bonus !
Each turret system will have its own program to take into account different maximum bearing angles and whether park positions are fore or aft.  The programs are essentially very similar but with a few variables changed.
Stepper motors are essentially far more accurate than other means of rotational drives.

For those not into electronics, think of each module as a programmable ESC driving a (stepper) motor.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on March 05, 2018, 08:43:53 AM
The 11 little microprocessors may seem overkill at first glance.

There are multiple benefits from distributing the processing across units, as however good these little boards are they can only ever do one thing at a time.

But the most significant reason is simply cost - the little Arduino Nanos are sub £3.00 - the ones I bought recently where just £1.53 each

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on March 05, 2018, 11:07:40 PM
I can't wait to see the methods of fitting and programing to come Bob.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on March 17, 2018, 05:06:02 PM
TARGET update...

This will be the layout of components for a firing turret

(http://modelboatmayhemimages.co.uk/images/2018/03/17/TARGET_F002.png)

C-3PO

Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on March 17, 2018, 05:12:10 PM
Most excellent C-3PO.  Nice Vero layout.  The non-firing turret boards will be similar but without the relay.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Brian60 on March 17, 2018, 06:13:53 PM
Lovely layout 3peeo, Why the 5v regulated tranny? Is that just for the nano board? From the specs for the nano it will take 20v to it Vin, I would have thought if you wanted to drop the voltage and make it regulated then a transistor down to 8v from 12v would be better, less wattage to lose as generated heat. Its not bent back so far that the heatsink is shorting the legs is it? What is the solid state relay for as well?
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on March 17, 2018, 06:22:59 PM
Hi Brian,

The 5v in the main is for the servo power supply which will pump fog fluid into the chamber heated by the thermistor (Geoff's gun smoke/fire system).

The relay board and stepper board are both 12v as are the stepper motors which is a little bit unusual for the 28BYJ 48 steppers.

I will run the Nano @ 5v regulated as I have seen articles about issues running Nano @ 12v as it's own voltage regualtor may well run hot - 12v is fine to run the Nano ONLY but you can't draw any current from the Nano 5v to run sensors/LEDs etc

New territory for me so may have to revise my plans.

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Brian60 on March 18, 2018, 08:15:22 AM
Gotcha, thanks for the further explanation.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on March 18, 2018, 12:03:43 PM
Bob,

You may need a bigger boat!!!

(http://modelboatmayhemimages.co.uk/images/2018/03/18/TARGET_F003.png)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on March 18, 2018, 01:12:55 PM
Bob,
You may need a bigger boat!!!
C-3PO

It does look intensive as 10 boxes and 12 Arduino's.  I will only need 4 relays of course.
A good job I am installing this in a 2.2M battleship, 30cm wide and 17cm hull depth.

The thought of wiring up the box internals is a little daunting, but the wiring between boxes is fairly minimal.
What we will have is each turret with its own fire control system, plus master and slave director controllers, and a digital compass.  All operating from one Planet receiver.  No wiring between hull halves, director control commands are transmitted independently to each turret with its own rotation arc/firing zones programmed in. 

I have to say C-3PO this looks one awesome set up, and technically complex as it involves seven turrets.

Bob K
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on April 30, 2018, 10:25:13 PM
TARGET

Model Boat Mayhem @ Wicksteed Park T-26!

(http://modelboatmayhemimages.co.uk/images/2018/04/30/Target_T-25.png)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 02, 2018, 03:12:51 PM
TARGET - Model Boat Mayhem @ Wicksteed Park T-24!

Final testbed components awaiting assembly


(http://modelboatmayhemimages.co.uk/images/2018/05/02/TARGET_TESTBED.png)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 02, 2018, 03:20:46 PM
Getting exciting  :-))  All those boxes to be filled with Arduino computer circuit boards.
I am still working on the turret mounting bracketry.  {:-{
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on May 02, 2018, 10:17:49 PM
Deep breaths Bob. pace yourself and you'll do fine.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 06, 2018, 03:36:50 PM
TARGET - Model Boat Mayhem @ Wicksteed Park T-20!

Almost ready for final testing

(http://modelboatmayhemimages.co.uk/images/2018/05/06/TARGET_TESTBED2.png)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on May 06, 2018, 03:51:23 PM
So left to right across the board equates to stern to bow.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 06, 2018, 04:30:11 PM
Actually, three turrets in the forward half (as cut) all firing.
Four turrets in the aft half, one firing.
The balance of firing and non firing turrets is more dictated by the weight distribution of the large batteries for firing turrets.  The aft end has the very large propulsion battery for the four big motors.
As much as I would like all seven firing that number of large SLA's is prohibitive.

I am beavering away at the stepper motor mounting mechanisms.  All tight for space

T-20  countdown to Wicksteed number descends rapidly.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 06, 2018, 11:27:57 PM
TARGET - Model Boat Mayhem @ Wicksteed Park T-20!

First 3 boards soak testing...

https://www.youtube.com/watch?v=TVYFQwYMJMQ&t=17s

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: derekwarner on May 06, 2018, 11:40:35 PM
Bob......disregarding scale calculation, the rotational speed shown for these 3 Blue Tubs appears fine :-))......in that they are very slow

Remembering the actual visual speed of train, is relative to the length of the mount to the extremity of the barrels

I think we must all agree that C-3PO has provided some brilliant hardware  O0 ....[deservedly potentially marketed as a kit]

Derek
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 08, 2018, 11:48:57 PM
TARGET - Model Boat Mayhem @ Wicksteed Park T-18!

7 turret control units powered up together for the first time

(http://modelboatmayhemimages.co.uk/images/2018/05/08/Target_Testbed3.png)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 09, 2018, 08:00:58 AM
Wow !  With all those flashing lights I wish I had made the decks of Perspex. 
It would look like Battlestar Galactica   %%

Or as Lieutenant-Commander Thomas Woodrooffe said in the famous Fleet Review radio broadcast of 20 May 1937.    "The ships are all lit up!"
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 09, 2018, 08:12:35 AM
Hi Bob,

Maybe you should rename the ship HMS Blackpool

Including the turret LED's there will be something like 103 leds in total of which only 28 are illuminated in the pic!

Crazy really but just down to leds being mounted on the modular components being used

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: timgarrod on May 09, 2018, 05:54:29 PM
Looks brillant C3po
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Martin [Admin] on May 09, 2018, 06:01:43 PM
 
Awesome!
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on May 09, 2018, 10:33:51 PM
I'm thinking Close encounters of the third kind  :-)) It shows it works.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 10, 2018, 10:58:57 PM
TARGET - Model Boat Mayhem @ Wicksteed Park T-16!

Evaluating stepper alignment process

https://www.youtube.com/watch?v=Oqwq_mFROzc

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 11, 2018, 06:27:04 AM
To quote Bill and Ted, "Most Bodacious".  If only we could borrow Rufus' excellent time machine.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on May 11, 2018, 01:55:36 PM

...…...Takes deep intake of breath and says.....


I think it best to leave history where it is just in case the time traveller makes the future even worse.


Ben Elton's novel 'Time and time again' is excellent for suggesting what could happen if we tried to change history!


It is in our genes to make mistakes and sometimes we make them when we think them right and sometimes we make them without knowing it.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 12, 2018, 10:48:53 PM
TARGET - Model Boat Mayhem @ Wicksteed Park T-14!

Testing gun fire - LED flash & 4 servos to pump smoke fluid - I will introduce timing errors so they don't all trigger at the same time.

The closeness of timing is quite amazing when you consider that half the kit receives it's instructions after they have been rebroadcast on on UHF having been already received on 2.4ghz

https://youtu.be/KP8kkbPv-Ng (https://youtu.be/KP8kkbPv-Ng)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 13, 2018, 07:15:44 AM
Amazing video C-3PO  :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on May 13, 2018, 12:36:42 PM
Assuming that your shopping list of components arrived in one week and the hull you want to fit the T.A.R.G.E.T system in has been built to suit it, (so no hacking out old stuff and innards etc), how long do you think it would take to fit and program the system?
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 13, 2018, 12:52:01 PM
Assuming that your shopping list of components arrived in one week and the hull you want to fit the T.A.R.G.E.T system in has been built to suit it, (so no hacking out old stuff and innards etc), how long do you think it would take to fit and program the system?

A very good question Iain  %%

I am beavering away at getting the turrets mounted and physically operable.  C-3PO is going flat out developing the software.  Before Wicksteed we aim to get the hardware (ship) married up to the clever bits electronically, but time is tight and so much to do.

Realistic answer is much more time than we have available, but we are going flat out to achieve the impossible with less than two weeks to go.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on May 13, 2018, 01:37:26 PM

That is great news chaps. Just so you don't think I am chivvying, I should have said that mine was an academic question with regard to others taking up the challenge. Naturally you are both pioneering the system and will have steps to take back as well as forward.


However far you get by Wicksteed, it will be a marvel to see and I look forward very much to see her, especially as I was there when the naked hull was put in the water for the first time!!


If you need a hand putting her in the water then you only have to ask Bob.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Mark T on May 13, 2018, 03:41:46 PM
C-3PO that is amazing  - talk about synchronised  :-))   I wish I understood electronics its definitely a black art!!
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 14, 2018, 10:57:37 PM
TARGET - Model Boat Mayhem @ Wicksteed Park T-12!

Had a play at introducing delays between turret firing.

Commanding each turret seperatley - the effect thought interesting is not what I am after so back to the drawing board...

https://youtu.be/OE4Q59t6XkU

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Colin Bishop on May 14, 2018, 11:24:44 PM
There are contemporary references to '''ripple' firing from forward to aft. Presumably to reduce the shock effect on the hull.


Colin
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Brian60 on May 15, 2018, 12:05:59 PM
I reckon I understand what you mean threepio.

Its the firing sequence, because its random you sometimes get 1,5,2,6,3,4. but then the next sequence as I observed was like 1,5,1,6,3,1,4, in other words it is sometimes firing one gun numerous times in the sequence, but it does look the bees knees.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 15, 2018, 01:12:03 PM
Looking spectacular C-3PO  :-))

The gunfire should be almost simultaneous. 

"When a full broadside was fired, the resulting sheet of flame was big enough to create the impression that a battle cruiser had blown up; it was awe inspiring".

Not quite as awe inspiring as T.A.R.G.E.T. though  O0
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 15, 2018, 01:33:35 PM
The gunfire should be almost simultaneous. 

Hi Bob/Brian

Bob - Yes that was my goal - I am addressing the turrets individually @ 100khz but it's not fast enough!!! ( or my code is napping somewhere) -  You can change a flag in the i2c communication protcol ( Wire.setClock(clockFrequency) )to talk over the network at 400khz which I will try later. -

I already have a back up plan just thought I might get away with the current solution.

My intention is that you will just be able to notice that they did not all fire at exactly the same time which is really easy to do - however I have made it more difficult as I am wanting to synch this to audio which limits my options.

Brian you spotted one of the problems ( multiple firing from one gun)  - the other is there is just to much time gap in the sequence....

Watch this space....

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 16, 2018, 07:53:56 AM
TARGET - Model Boat Mayhem @ Wicksteed Park T-10!

Having used the TARGET test bed system for a few days now part of me can't believe that it might just actually work - it's come a long way since Bob K's first post on  December 23, 2016  http://www.modelboatmayhem.co.uk/forum/index.php/topic,56800.0.html

We are using a "pot" control on the 2.4ghz RC TX to select the turret position - one thing that I have noticed is that the control is a little "coarse" in being able to put the turrets to a desired position accurately.

I might experiment using a multi position rotary switch to simulate an old fashioned "resistance ladder"  - this way you could very accuratley command the turrets to  predetermined positions.

C-3PO

Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: bfgstew on May 16, 2018, 09:03:27 AM
Just a thought C-3PO, how about a 10 turn pot with a graduated dial, like on a safe lock? Should give 10 times the accuracy. Map turret rotation position to number on dial for quick positioning.


Stewart
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 16, 2018, 11:11:38 AM
Hi Stewart,

That's an interesting suggestion...

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 17, 2018, 07:15:57 AM
TARGET - Model Boat Mayhem @ Wicksteed Park T-9!

Turret training limts and Free to Fire zones all working for forward facing turrets - the aft facing turrets seem to be dancing to a tune all of their own - Maths was never my strong point.
Master and slave control boards still to be designed and made ( currently on stripboard) before this all gets fitted into Bob K's boat on Tuesday - pressure!!!

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 24, 2018, 08:55:17 AM
TARGET - Model Boat Mayhem @ Wicksteed Park T-2

I think Bob and I maybe redefining "last minute" with this project - HMS Agincourt will only be fitted out with the TARGET system an hour or so before it hits the water @ Wicksteed Park
Frustration with defective stripboards - not one but two (tracks joined with rogue copper) led to lots of head scratching and significant lost time. You could only see the track joins under a powerful magnifying glass

Finally we have working Master and Slave control unit - however the rear facing turrets still have a mind of their own...

Here is the Master and Slave control units (Mcu & sMcu)

MCU

(http://modelboatmayhemimages.co.uk/images/2018/05/24/TARGET_Mcu.jpg)

sMcu

(http://modelboatmayhemimages.co.uk/images/2018/05/24/TARGET_sMcu.jpg)

Hopefully the next 48 hours will be constructive

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 24, 2018, 10:01:28 AM
Quote
I think Bob and I maybe redefining "last minute" with this project - HMS Agincourt will only be fitted out with the TARGET system an hour or so before it hits the water @ Wicksteed Park

You can say that again  %% 
Please everyone remember that ship and electronics have not yet been formally introduced to each other, and the hull only met "first water" here yesterday.

Bob K
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on May 24, 2018, 10:03:28 AM
You are a top chap C3PO. That has been a lot of challenging work, and I look forward to seeing it this weekend as much as I do the ship it is installed in  :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: bfgstew on May 24, 2018, 10:14:28 AM
Success or failure, this has been a monumental effort by you both.
Hope you get it working and get a video on line to see it in all its glory........👏👏👏👏
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 24, 2018, 10:15:26 AM
Totally agree   :-))

If we can get one turret turning, better still turning and FIRING, this three-way collaboration could be eligible for model boating's equivalent of Nobel Prizes
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: tsenecal on May 24, 2018, 04:03:26 PM
Hopefully the next 48 hours will be constructive

C-3PO


why did i read that as "Hopefully the next 48 hours will be conductive" ?
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Colin Bishop on May 24, 2018, 04:07:33 PM
Conductive? Sounds electrifying..... ok2
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: derekwarner on May 25, 2018, 12:01:23 AM
Electrifying.....Nobel Prize or Noble Prize?..............whatever it is, it certainly be most deserveded.... :kiss:...
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on May 25, 2018, 07:43:49 AM
It really does seem that the universe does not want this project to be a success.

My mcu control unit stopped working last night - jurys out - I don't know why - having tinkered with it of an hour to see if I could breath life back into it I gave up.

Sporting a new "purple" 459 Mhz antenna a new Mcu was born this morning @02:30

(http://modelboatmayhemimages.co.uk/images/2018/05/25/mcu2.png)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on May 25, 2018, 08:23:18 AM
Yippes  >>:-(
That is SO frustrating.  I feel really bad over how much effort you are putting into this. 
The least it could do is behave itself.  Would thrashing it with a dwarf tree help?  Probably not . . .
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on June 06, 2018, 09:38:45 AM
TARGET - Post Wicksteed Park update

Events that led up to the Wicksteed Park weekend with some "unfair" hardware challenges impacted on the implementation of TARGET in Bob's HMS Agincourt.

Basically we ran out of time on what was quite an ambitious objective.

However we did get the master and slave controller installed along with 3 turret controllers all plugged into Bob's 2.4 ghz radio - all working as expected apart from possibly one significant thing! - it was possible that the software would drive the smoke fluid pump either in the wrong direction or past a physical limit. This was an oversight and something that I had not anticipated in the build up to Mayhem - easily sorted but not on the day.

By now it was late in the afternoon and Bob needed to get to Mayhem @ Wicksteed Park

So the latest with TARGET is that Bob and I are working to get his HMS Agincourt boat fully equipped with the TARGET system but at a slower more relaxed pace

Other issues I had with rear facing turrets dancing to their own tune, training limits and free to fire zones are all coded and working well.

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on June 06, 2018, 11:12:22 AM
Frankly, it was a very long shot to get all this installed and tested on the day Wicksteed started. 
However, I appreciate how much was achieved in so short a space of time.

It took quite a bit of time to re-map my Planet T7 receiver.  C-3PO had used a Spectrum for his set up.

The mechanical issues were largely my failure to appreciate the inter-box wiring requirements.  I am now working to greatly improve this situation using brass rod "Busbars" embedded under the deck panels, for DC power distribution and the 3 wire networking bus.  I am learning!

Also, although DC wiring was there for the thermistor batteries, I now know only the +ve is switched on the boards.  I will also be providing DC connectors to made deck removal easier.

Thankfully there is now no time pressure.  Many thanks C-3PO  :-))
Title: Re: T.A.R.G.E.T - Rotating 3 gun turrets?
Post by: C-3PO on June 14, 2018, 02:55:30 PM
Next candidate for the TARGET system - only 1 hull and 3 turrets

(http://modelboatmayhemimages.co.uk/images/2018/06/14/KGV.png)

Original ROYAL NAVY CAP TALLY?
(http://modelboatmayhemimages.co.uk/images/2018/06/14/KGV_002.png)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on June 14, 2018, 03:14:14 PM
Not built already  %%   Must be an 'as completed' picture?

Excellent choice.  Beautiful battleship. 
I estimate only 6 Arduino boxes:  MCU, 3 x turret controllers, compass and audio?

I will watch this build with avid interest  :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Geoff on June 14, 2018, 03:15:35 PM
Just as a thought maybe you could get the secondary armament to track as well?

Cheers

Geoff
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Netleyned on June 14, 2018, 03:18:17 PM
Could be an original cap tally,
They were not so shiny then.
But I suppose someone is doing
replicas.
Cap Tallies R Us comes to mind {-)
Ned
Never had Cap Tallies.
First Ship Fisgard.
Motto
If it don't work, hit it with a
Hammer.  %%
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on June 14, 2018, 03:29:25 PM
Bob - yes ARTR - just add water...

Geoff - Snap - see below pic for the new baby stepper motor I am playing with - to the left is the ones in Bob's HMS Agincourt

Neyleyned - could be a fake who knows - if you see it in the flesh it does look like it's old, the embroidery thread seems metallic'ish

(http://modelboatmayhemimages.co.uk/images/2018/06/14/KGV_003.png)

C-3PO



Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Geoff on June 14, 2018, 03:54:09 PM
Interesting, how much power do the small stepper motors give compared to the larger version? miniaturisation is key these days!

Cheers

Geoff
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on June 15, 2018, 01:34:16 PM
Interesting, how much power do the small stepper motors give compared to the larger version? miniaturisation is key these days!

Cheers

Geoff
Hi Geoff,

Re the micro stepper - not sure what the power output will be - not a lot - I have just realised that the one I have does not have a gear box so all but useless...

So same motor can at the bottom but metal gear box inside plastic casing

(http://modelboatmayhemimages.co.uk/images/2018/06/15/Stepper2.png)

I have ordered a couple of ones with metal gearboxes - once I know more I will update you

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on June 27, 2018, 12:13:35 PM
Geoff,

These just arrived - must have been on the slow boat from somewhere - initial results are that they have quite high torque

I'll update you when I know more...

(http://modelboatmayhemimages.co.uk/images/2018/06/27/MicroStepper.png)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on June 27, 2018, 02:40:17 PM
Now this gets interesting.  Those steppers are truly tiny compared with mine.  I guess you intend them for your HMS King George V.  I wonder if they would drive my Agincourt turrets?
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on June 27, 2018, 03:33:57 PM
Hi Bob,

Yes I want them for KGV secondary armaments - I will still use 28 BYJ 48 steppers (same as your HMS Agincourt)  for main 3 turrets unless these new ones prove to be man enough - the 28 byj 48's are Unipolar - these little blighters are Bipolar so more grey cell being expended on learning - love it!

I have just ordered some even smaller steppers (£0.20p each) that I think either came out of a hard drive, cd drive or maybe a camera (autofocus) - when you scratch the surface you find stepper motors popping up in all sorts of places - they where used (still are in many cases) for dashboard dials ( speedo/ rev counter etc) in cars

Regards
C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on June 28, 2018, 08:03:43 PM
Still refining smoke production

https://youtu.be/ncedtQVQ5-w (https://youtu.be/ncedtQVQ5-w)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on June 30, 2018, 04:20:06 PM
Micro stepper test - this little motor has got some guts!!!

https://youtu.be/g1PAcsJ6Eok (https://youtu.be/g1PAcsJ6Eok)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: tsenecal on June 30, 2018, 08:31:03 PM
C-3PO...


do you have any links to both the micro stepper motor and the motor driver you are using?
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on June 30, 2018, 09:27:10 PM
Hi tsenecal,

I intend to use them on secondary armaments on a KGV

I got mine from eBay uk - I don't think they are new - I think they have seen life in another piece of kit

You will find them with varying gearboxes - but the metal motor can is the same, no doubt produced by the tens of thousands

Google - 15mm Body Geared Micro Stepper Motor and you will find them or maybe  15BY25 - just make sure they come with the gearbox or they are useless

EG - https://www.alibaba.com/showroom/15mm-stepper-motor.html (https://www.alibaba.com/showroom/15mm-stepper-motor.html)

http://www.dx.com/p/5v-micro-angle-high-torque-15mm-2-phase-4-wire-stepper-gear-motor-white-363007?m=0 (http://www.dx.com/p/5v-micro-angle-high-torque-15mm-2-phase-4-wire-stepper-gear-motor-white-363007?m=0)

I am using a basic Adafruit motor control shield as I had one already - can use any simple cheap bipolar stepper driver - perhaps Pololu or Easydriver

In the video they are running on a 3v supply

Hope that helps

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Capricorn on August 25, 2018, 05:17:06 PM
See video of an operating compass directed fire control for RC:

https://www.youtube.com/watch?time_continue=196&v=mgtidK7LFhA (https://www.youtube.com/watch?time_continue=196&v=mgtidK7LFhA)

It generally does or can do what I think the target system is intended to accomplish minus a bell and whistle.  I conversed with dreadnaught quite some time ago about this and worked on it for a while concurrently.  It's currently being installed on 1/200 Bismark.  The standard 28 BYJ 48 motors work just fine for this application, and the function is rudimentary, the director is governed by the compass and the turrets simply follow the director as programmed.

The target system needs a "shot in the arm" so to speak, it's been a long time and seems to have stalled, I'd like to see it concluded.  Best wishes, Cap
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on August 25, 2018, 06:07:48 PM
Fear not, the system development will be back underway shortly I am assured.

The original plan to get it fully working for Wicksteed was highly optimistic, bearing in mind the ship and the electronics test rig being a hundred and fifty miles apart until that day.  We did get about 60% of it installed but ran out of time.  What was installed did work, although the wiring needs a lot of tidying.

I have every confidence in C-3PO who has put a huge amount of time and resources into this.

Q:  How long did it take to commission HMS Queen Elizabeth?  Getting electronics to successfully interface with ship hardware is not the five minute job of fitting an ESC.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Capricorn on August 27, 2018, 10:25:04 PM
Who's Wicksteed?  Haven't seen any posts by him/her  ;) .  Cap



Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: mrlownotes on August 27, 2018, 11:27:58 PM
Who's Wicksteed?  Haven't seen any posts by him/her  ;) .  Cap


I see that Bob's wording may have suggested it, however Wicksteed is not a person but the location of a very prestigious annual model boating event in the UK.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on August 28, 2018, 11:32:43 AM
Sorry mrlownotes.   This is Model Boat Mayhem, and Wicksteed Park is this forum's major national event.
We were hoping to have the TARGET system running for the event, but ran out of time.

More news will follow . . .
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Martin [Admin] on August 28, 2018, 11:41:26 AM
Who's Wicksteed?  Haven't seen any posts by him/her  ;) .  Cap

See: http://www.modelboatmayhem.co.uk/forum/index.php/topic,54588.msg642001.html#msg642001
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on March 26, 2019, 10:02:56 PM
Just started installing the TARGET system in this beauty so maybe some more smoke on the water at this years Model Boat Mayhem weekend @ Wicksteed Park

(https://modelboatmayhemimages.co.uk/images/2019/03/26/1-128-Fleetscale-Hms-King-George-V-Battleship-Full-Radio-_57.jpg)

Also hopefully Bob's amazing HMS Agincourt will be on display sporting the all singing and dancing version of the TARGET system.

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on March 27, 2019, 01:08:32 PM
Looks good.  What scale (size) is she?   "Only" 3 turrets to turn  :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on March 27, 2019, 05:52:42 PM
Hi Bob,

Fleescale hull - 1/128th 69" (1.76m)

And yes "a walk in the park" ONE hull to run cables end to end and just 3 turrets but the little guys on the side are trying to get my attention hence I am investigating some small steppers

C-3PO

(https://modelboatmayhemimages.co.uk/images/2019/03/27/8.jpg)

(https://modelboatmayhemimages.co.uk/images/2019/03/27/7.jpg)


(https://modelboatmayhemimages.co.uk/images/2019/03/27/2.jpg)
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: ballastanksian on March 27, 2019, 10:05:31 PM
I have never liked this class as much as her older cousins, but they still make beautiful models, especially well executed ones like this  :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on April 20, 2019, 06:35:17 PM
Hated geometry at school - hate it even more now!

https://youtu.be/xKrzl6cJadU (https://youtu.be/xKrzl6cJadU)

Trying to make a shore based visual feedback system for the TARGET system - (note this is a demo only not using real data so the behaviour of the hands is not what you may expect)

The intention is one hand would indicate the heading selected via the pot know on the RC TX and the other hand would indicate the current position of the gun turret...

A few more whistle and bells up my sleeve....

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on April 20, 2019, 08:43:24 PM
Neat video clip, but not sure I understood what was happening there ?
There will of course be a lag between bearing with changing ships position, and turret coming round to try and keep on target.  Of course there will oft be desired turret orientations in which the guns cannot bear.
However, both pointers seem disinclined to match up into correct bear/fire angles.
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on April 20, 2019, 09:10:40 PM
Hi Bob,

Your observation is spot on - that's why I posted the text

"note this is a demo only not using real data so the behaviour of the hands is not what you may expect"):)

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on April 20, 2019, 10:20:04 PM
Sorry Sir, I was just trying to figure out what you were doing  %%
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on April 21, 2019, 08:51:49 AM
Hi Bob,

Apologies - it would be more like this although slower in movement

https://youtu.be/8J8DiYPbGCk

C-3PO
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on April 21, 2019, 03:50:31 PM
Now that looks the biz'   :-))
Realistic tracking of turret as ship turns and guns attempt to bear on target. 
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: dreadnought72 on April 21, 2019, 07:44:55 PM
There's a chunk of the flowchart I wrote ages ago which handles "the direction you need the turret to turn" whether the desired target angle is positive or negative and whatever the current turret angle is. Might help you, or you may already have cracked it?


Andy
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: Bob K on April 22, 2019, 01:19:46 PM
From a purely practical point of view a model boat will generally be sailed in a large oval (1700x 700m).
On selecting a bearing to fire on the TARGET system will ascertain which turrets can train onto that bearing, either to port or starboard. Those that can bear after rotation completed will fire when commanded.
By this time the model may have started a 180 degree turn, and calculations get more tricky.
Some turrets will no longer bear, and others may have to be counter-turned to pick up the target on the opposite beam.  This is what makes the Ardunino computers really earn their keep.

Of course "lesser" ships that (only) have to turn guns to port or starboard 90 degree can fire once on each leg of their oval.

Can we achieve a much better rate of fire than twice per sailing oval on a lake?

Personally I believe we can.   :-))
Title: Re: T.A.R.G.E.T - Rotating Seven gun turrets?
Post by: C-3PO on April 22, 2019, 06:26:37 PM
There's a chunk of the flowchart I wrote ages ago which handles "the direction you need the turret to turn" whether the desired target angle is positive or negative and whatever the current turret angle is. Might help you, or you may already have cracked it?


Andy

 Hi Andy,

Thank you for your thoughtful offer – I cracked the stepper bit (-180/+180) many months ago, took me some while longer to finally get my head around the turrets facing the stern which I know is simple but my original approach was floored.
 
Bob and I installed part (half’ish)  of the TARGET system into his HMS Agincourt for Mayhem 2018, but as such was not really anything to get excited about

After this point the project gathered dust for many months as other things took it’s place – it was only a few weeks back that I revisited the subject.

All the boat-based functionality is working even thought for the purists out there it’s only a “bench” model and may not translate into a working “ship” based solution - really?

I have been working on some shore based functionality which hopefully may see the light of day at Model Boat Mayhem weekend at the end of May 2019

Part of that functionality is the shore based visual feedback system which in itself presents me some challenges not allowing the "pointer needles" to go through the 180 degree point and instead force them to go via zero degrees to get to the other side - this is mainly as it's not a language I am familiar with but all adds to the fun!!!

Regards

C-3PO