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[Mad_Mike]

HI Mike
     I must admit that the design of a sonic link for under water for controlling the sub would probably be targeted at the modeller  who wont's some thing that he can use say at a show and not have to worry about a peg board and who is on what channel so they can sail at what ever time they wont

    Where i used to sail the sub of mine i have seen me being about 3FT down in the water and being well over 300FT away even as though you could not see it you could see a lump on the surface of the water so you could tell where it was, i have even controlled a sub under the ICE many years ago i must be mad and yes i did get it back.

Mike i have been fitting LF antenna in today its took all day what a pain in the neck. Just got to do a bit of painting on the pressure plate hatch
  Sub John

The technology could go in all kinds or directions, modeling, science, search and rescue, military.
how much pressure does the hull off your sub withstand?

[sub john]

HI Subculture
     Thanks for your thought's on making bits for subs was going to stop away from making things like levelers like you said there is to many making them now, not worth trying to compete, whats your thought's on making a water switch that will switch the sub on when you put  it in to the water could also have reg circuit to run radio, unit would have on switch to by pass water sensors to test on bench or what ever.  Stand by switch would be on and ready for sub to be put in water to work

      Things that we are going to do is not just for subs working on a lot of telemetry gear to fit in planes boats of any model you can think of. Just finished designing high voltage reg  will do 50V down to 5Volts of 6volts which you can select
             Sub John

[sub john]

HI Mike
    You asked how much pressure the hull of my sub would take, well the hull is made of Kevlar woven cloth, if you fired a shoot gun at the hull at about 6ft away it would crack the jel coat but it would not go through the hull it is the same stuff that bullet proof panels are  made of it is very strong i have sat the sub at about 25 FT down on the bottom.

     I don't know wheather there would be a market for  sonic system for controlling a model  sub may be it is like Subculture said people would just stick to 40MHZ or what ever, but there is loads of other bits that can be made i think there would be a market for the telemetry stuff as quite a few people seem to be getting interested in that now we will see. But to just make things just for subs would be a big mistake as i don't think there is a big enough market, a lot of people like to keep things simple, if thats what they wont its up to them. I like to see how far i can take it but thats me i like the challenge
    Sub John

[Subculture]

I use loggers by Eagle tree. These record data to memory like voltage, current, motor RPM, temperature. Can also record other things more valuable to flyers like GPS, altitude, airspeed.

It's a handy device as you can see very accurately how the motor is performing with a certain prop combination in a dynamic setting, as opposed to running it up in a bucket of water, which only gives a rough idea.

Eagletree also offer devices that can work transmit data, but these are no good in subs as the frequency is too high. However to be honest, I don't think I would use telemetry much, I prefer to analyse the information on a laptop, and the view the data plotted on a graph.

The water switch sounds like a good idea, haven't seen anything else quite like that on the market. What sort of price could you build it for though? I'd say it would need to be sold for about £20 if you want them to sell.

I think the bottom line with this sort of thing is, do you want to make items to sell and make money from, or do you want to develop products as an intellectual pursuit and maybe sell a few as a paying hobby?

I see a lot of people saying 'build this or that', but when it comes to fruition and it's time to cough up, they evaporate like the morning dew. 

[Mad_Mike]

once you get your sub on youtube doing what it does other people will want to have a go too. yeah wont be everyone, but you not the only person in the world to want to take it to next level 

[sub john]

HI Subculture
     I have got some Eagle Tree telemetry gear, and yes data loggers can be usefull but some of the telemetry gear that we are designing you can see it real time on screen if you won't all sorts of different data but you could all so data log it on to laptop to analyze it later, but to be honest a lot of this gear that we have been designing is not going to be for model subs again i don't think there will be a big enough market.

Thought about designing unit for piston tank controll which would be digital proportional I think the one that Engel sell is only proportional the last bit of the tank but i might be wrong. Have been playing about with piston control board that Dave has done the soft ware for on the AMS but myself i have never liked the idea of micro switches to switch tank off at the end of the run, have reworked the circuit so it has hall effect switches that will switch off logic for driving fets. Have thought about using in-fa red light to get feed back from prosition of piston in tank as would like to do this with know moving parts. One of the things i do like about subs is you can come up with all sorts of new ideas to build in to a model sub

Price of water switch about £24 one of the things with using a water switch the water sensors should not have DC on them as it leads to corrosion really need to see AC to stop this happening which this unit will have
                Sub John

[sub john]

HI Mike
      Wouldn't get your hopes up to high Mike it might sink and not come back up yet if it does sink and can not get it back up i don't think any one will bring it back to the surface unless they are built like KING KONG HA HA  because I'm not going in to fetch it I CAN NOT SWIM HELP !!!ANY ONE KNOW THE PHONE NUMBER FOR INTERNATIONAL RESCUE THUNDER BIRDS ARE GO AND ALL THAT.

  I can remember when a friend of mine Derek got his fingers stuck in the vent at the front could not get his fingers out and i was taking him down to Davy Jones Locker at Charnwood waters HELP IM GOING DOWN WITH IT  I don't think i can say what he really said i would be band off mayhem
     Sub John

[Mad_Mike]

pfft negative

[Subculture]

Thought about designing unit for piston tank control which would be digital proportional I think the one that Engel sell is only proportional the last bit of the tank but i might be wrong. Have been playing about with piston control board that Dave has done the soft ware for on the AMS but myself i have never liked the idea of micro switches to switch tank off at the end of the run, have reworked the circuit so it has hall effect switches that will switch off logic for driving fets. Have thought about using in-fa red light to get feed back from position of piston in tank
water sensors should not have DC on them as it leads to corrosion really need to see AC to stop this happening

Engel do several piston tank control boards. The ones with a pot for feedback do as you say only proportionally control the last few inches of travel, but that is mechanically limited by the pot they use- you can replace that with any pot of about 5-10k range with more travel if you want control over a longer length. Engel argue that having proportional control of a piston tank that is used for main and trim duties is a waste of time. I think that's a fair point to be honest.

They also do a board with encoder feedback, and that can be set for full proportional control of the piston tank length. The disadvantage with encoder based systems is that they're not absolute like a pot. Small disadvantage though.

Interesting point about micro switches. I think people prefer these as they're considered fairly dependable. People may not trust a logic switched solution.

One idea I had for a piston tank controller, which I haven't seen tried yet, was to have a small unit that slots in between the receiver and an ESC. It would take feedback from a pot or encoder, and dependent on the receiver signal send a pulse to the ESC to go forward or reverse.

Such a unit could be made very small, it would remove the need to supply a complete board, and ESC's are very cheap these days, and/or folk often have a spare or two kicking about.

[sub john]

HI Subculture
    Didn't realize that Engel did so many different boards to fit there piston tanks.
  Using encorder with disc do they use IN-FA red light or hall effect sensors, trouble is with using encoder on the end of shaft to get accuracy  you need to have quite a few pulses to encorder to get accuracy really need to have more that one pulse per one rev of the shaft even two of three is not enough to get the controll loop to give you accuracy

You said about using ESC'S to control tank with feed back pot or encoder i did pretty much the same thing many years ago when i had a Engel Gato but unit was all so linked to leveler so what happened back piston tank would hunt to keep sub level, sub all so had leveler controlled trim tanks it all so had IN-FA red cut outs for piston ballast tanks no micro switches i hate the things give me soiled state any day. must have done this about 28 years ago sat hear and can not believe how long ago it was, this was before my son was born
     Sub John

[sub john]

HI Mike
    Have fitted LF antenna in sub but seem to have a problem, sub seems to be picking up a lot of noise and i don't know where from but has only started since i fitted the antenna around the top of the sub even if i disconnect it is still there giving this noise on all the electronics example servo twitching depth control twitching and all sorts of daft things sat thinking about it and was wondering if it was picking up long wave radio station. But did wonder if i have set up a inductive loop around the sub what a pain trouble is there is so much electronics in this thing now where do you start.

   But what bugs me is when you disconnect antenna for LF  it is still there makes you feel like RIPPING IT TO BITS
   SUB JOHN

[Subculture]

do they use IN-FA red light or hall effect sensors,

They use a hall effect sensor, they suggest a minimum of four magnets for adequate levels of trim. On an Engel tank that should give you control to within a gram or two. Tanks with smaller pistons would give even more accuracy, but to be honest I think that is sufficient. Most people are content with water pump ballast systems with bang-bang control and zero feedback.

[Davy1]

I was having a look at the latest proportional (by Hall effect sensor) control board from Engel  while I was in Dortmund. I have to say it looks good and is sensibly priced at Euros 60. (I still don't see why they persist in using relays though.)

A colleague bought a  couple of the boards and we eagerly await his experiences.

By the way, John, I am still passing on enquiries about the "modded" car tilt level controllers directly to you, if you want to do them that is, otherwise say no. (Alf is the latest person to ask)

David

[Subculture]

I still don't see why they persist in using relays though.

Electrical isolation perhaps? The sole solid state piston tank control board Engel supply, is the one that users have reported problems with, e.g. glitching.

Although relays are relatively old tech, they are simple, relatively inexpensive, and very reliable if correctly specced.

[U-33]

Tell me, all you electronic experts...what's wrong with using two microswitches and a servo to switch piston tanks in/out? My Patrick Henry performed faultlessly all the time I had it with common or garden microswitches, 'borrowed' from a leading communication company by Vic Felton.

[Subculture]

Why choose Jaguar over a mini, they both get you from A to B? One offers more refinement than the other.

A servo controlling a pair of microswitches isn't really that straightforward when you think about it, it's just that the technology is well hidden behind a plastic case. Essentially, by making the piston tank proportional, you are turning it into one large servo, with beefed up power components, therefore bypassing three extra points of failure- the two microswitches and the servo itself. In real terms the proportional tank is a simpler gadget than the one controlled in bang-bang fashion.

[U-33]

I'd have thought that two microswitches and a servo is about as simple as it gets when it comes to controlling a piston tank. No fancy electronics to go wrong, fail or burn out, just a couple of switches @ a pound or so each, as against many pounds worth of electronics for a proportional controller.

If a microswitch does fail...it's cheap and easy to replace, but if a proportional controller fails...it's out with the flexible friend and avoid the wife/girlfriend/boyfriend/partner for a while.

And as for the finesse in controlling the tank with a microswitch...well, do we REALLY need the capability of pumping in/out a drop of water? I bet you'd be hard pushed to notice the difference between a switch controlled tank and a Bruggen/Engel/whoever proportionally controlled tank in a sub out on the water.

[Subculture]

Servos are little technical masterpieces. Inside your average 'el cheapo' servo you'll usually find a microcontroller, h-bridge and feedback pot, exactly the same things you will find in a proportional piston tank controller (sometimes an encoder in place of a pot), only with a beefed up h-bridge. Having said that, for very small tanks, e.g. one based on a syringe, normal servo electronics will usually suffice,as you only need a watt or two of power.

Servos are very cheap through mass production. They used to cost a lot more years ago. Piston tank boars sell in considerably lower volume, so the price will be higher. Fault finding on such a board wouldn't be too hard. Some boards use SMD components, which can be tricky to test on and/or replace, but if your board is designed with through hole components, it's pretty straightforward provided you're comfortable with a multimeter.

Fit what you feel happy with, but proportional systems are very slick, and provided they're designed well, are reliable.

[U-33]

Ah, now you've wandered again...the servo and two microswitches is for those of us who don't know one end of an H bridge from the other. I wouldn't know a SMD component from a baked apple, especially if it had a through hole, let alone know how to install or repair it.

A servo with a inch square of styrene sheet on the top and two microswitches is a different kettle of fish though...dead easy to make and install, and easy to repair/replace.

Those famous four letters spring to mind.... K.I.S.S.

 

[Subculture]

Well the point I was trying to make was that a servo isn't a simple device.

[U-33]

No, absolutely true...my point though, was that from your average Joe's point of view, a servo and two microswitches is an awful lot easier to make up, install and set up than a fully proportional, all singing, all dancing, electronic controller. And a lot cheaper too...

I've used both types, and some inbetween as well, but a good old servo with a couple of microswitches takes some beating for controlling an average ballast tank.

Micro piston tanks in small boats (such as Nigel Edmonds' little Turtle) are another matter, a proportional controller is a necessary asset...but in something the size and weight of the Patrick Henry, you don't really need such a delicate touch.

[sub john]

HI ALL
     A lot of what Subculture has put is fair comment and a logical out look, he seems to be seeing it for what it is if you are using a servo to control two micro switches yet you are using electronics to make that work a servo then why not take it a step further and go solid state electronics no moving parts. If you went in to proportional control of piston tank you can start to make control loops to make a model sub hover in the water but i suppose it is how far you won't to take it.

  I have seen a lot of model subs that are basic electronics inside but are not reliable, if a model sub uses micro switches on a servo if the sub goes out of radio link the  receiver inside of sub can make servos go to end stop and i have seen this rip micro switches out you don't get this problem with electronics but this is just my own view.  I know you can fit radio fail safes to what ever channel you won't to try and stop this problem but i would sooner stick with solid state electronics.  The smaller Engel sub that i had was solid state electronics and no micro switches and that worked great for many years before i got rid of it and it was very reliable i never touched it just charged it and took it out
      Sub John

[tsenecal]

One idea I had for a piston tank controller, which I haven't seen tried yet, was to have a small unit that slots in between the receiver and an ESC. It would take feedback from a pot or encoder, and dependent on the receiver signal send a pulse to the ESC to go forward or reverse.

Such a unit could be made very small, it would remove the need to supply a complete board, and ESC's are very cheap these days, and/or folk often have a spare or two kicking about.

and/or folk could use a BRUSHLESS controller if their slightly odd nature allowed/forced them to do so.  :)

[Subculture]

I would be cautious using brushless motors/controllers on a piston tank unless they were sensored, owing to the start up characteristics being somewhat different to brushed counterparts.

Your average servo tends to be capable of 4-5 watts output, this is enough power to drive smaller tanks (up to 50mm piston diameter). If we are prepared to remove the pot from the casing and attach it externally to the piston via a lever, and if required modify the output gear for continuous rotation, you have the makings of a very inexpensive proportional dive system.

The snag lies in the servos speed, on average servos tend to wind at about 50RPM. If this is connected directly to a threaded spindle, in the way most piston tanks are actuated, the time taken to move the piston will be extremely slow unless the stroke is very short. This can be cut down by gearing-up the output of the servo, say 2:1.

You can use a rack and pinion, which gives us the opposite problem- now the piston moves too fast. The ideal for rack and pinion is an output of about 10-15RPM, so our servo needs further reduction of 4 or 5:1 in order to generate sufficient torque.

A third option is to ditch the servo mechanics, and just use the amplifier board and feedback pot, and hook it up to a third party motor and gearbox. Robotics suppliers like Pololu sell miniature geared motors at competitive prices, which being sized about the same as most sero motors and with a 3-6v voltage range are ideally suited to the task. I expect most modellers have a servo or two in the scrap box with a stripped gear train or a burnt out motor, but perfectly serviceable electronics.

[Ramius]

Hi All!
I was hoping to ask Sub John a couple of questions?
1. How he made out with his compass?
2. Does he have a depth gauge?
3. Most important does he have a speed sensor?

Thanks, Ed