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[Arthur_G]

New guy alert...





I am building the Hobby Boss 1/200th scale model of the Japanese pre-dreadnought battleship Mikasa.
My idea is to create the control systems myself using off the shelf Arduino components, this presents some challenges with when to install the electronics in the timeline of building a plastic model kit.  I've not built a (floating) model boat for many years.
I have created this prototype frame on the laser cutter and I’ll fit the electronics into it and get the Arduino code working and tested before it goes into the kit. Well, that’s the idea.  The prototype is much smaller than the hobby boss kit, but there's enough space .
The bread board in the foreground has a digital compass and is displaying the heading. The display has a blank line but thats just an interaction between the display refresh rate and the shutter speed on my camera phone.  The required heading and the direction each of the two main guns should be pointing at is set using the potentiometers and displayed. Originally I had three servos connected which represented turning the rudder and and the two main guns to the requested bearing.
The two servos turning the main guns can be seen poking out of the deck of the prototype and the rudder (rather un-scale!) is hanging off the back of the model.
At the top of the picture you can see two breadboards each with an Arduino and 2.4Ghz transceivers. These two breadboards talk to each other two way over distances suitable for the model boat. I haven’t tested them over water yet but there are more expensive transceiver units available so I can upgrade as necessary.
On the right are the electronics that I have to fit in the prototype and on the left with the gears are the actual geared stepper motors that I will use on the guns in the 200th scale model.


Although I'll use stepper motors for the actual model (the subject of a separate prototype at some point in the future) I did try and get more than 180 degrees of throw.

The picture shows a servo modified for continuous rotation but I've left the internal pot connected to the gears, the external trim is setting the centre and is connected to the servos internal board in place of the servos pot.  The extra wire is from the internal pot and I attach that to the arduino to grab the actual position of the servo.  The code sends a pulse to get the servo to turn very slowly and samples the internal pot for postion.  The track on the internal pot goes a bit further than 180 degrees and I was able to stretch a bit more from it, however being a cheap servo it didn't move nicely and I decided to just use the servos with 180 degrees travel for this prototype.

[C-3PO]

Hello Arthur,

Looks like you have an interesting project of discovery ahead of you with the collection of tech on your desktop.

From what I can see you will be approaching the subject from a different perspective to some of us so it will be interesting to follow your progress.

There is a small group of us that belong to a "RC Arduino" forum ( https://login.proboards.com/register/6696601 ) - you would be most welcome to join ( I post this forum link with Martin's blessing)- it allows low level tech discussion without cluttering up the Model Boat Mayhem forum where we tend to just post the highlights of our exploits.

Looks like you are using Nrf24l01 2.4Ghz boards - if you haven't already you may want to checkout the allocated frequency and application on the OFCOM website ( https://www.ofcom.org.uk/spectrum) to ensure you stay legal with the use of the RF spectrum.

Regards
C-3PO