PISTON TANK DRIVE BOARD

HI,
@david

PICTURES,PICTURES Please.
THANK YOU

I didn't take any I'm afraid (I only have 2 hands!) Also I can't post pictures on here for some (still) unknown reason.

David

Too bad for the pictures and because You have only 2 hands!.
To ad pictures is ended a Little tricky.Iknow how to do it but is difficult to explain,but I wheel do my best:
- soon as You open the "Post a Replay",on the second line of squares nr2 square is "Host an Image",
- left click on it,it wheel open a window "WWW.SERVIMG.com",go "BROWSE",choose a picture,click "HOST IT",a new window wheel aper,click "COPY",a new window again.Is going to ask You "ALLOW ACCESS",click "ALLOW",and then You have to move the MOUSE on that 1" space right between the window with "WWW.SERVIMG.com" and the normal window,LEFT CLICK > "PASTE" and finally click on "PREVIEW" on the bottom of Your page to See if is OK.
-

What is the status of the board, also you seem to have some documentation available, could you please send me a copy.

Hi Dain,

Sorry about the delay I've been on a little holiday in Wales.

The board (with its slight revisions) is all done and I've been using in 3 of my subs for the last few months.

Probably the best thing if you want to have a go with one is, as a member, get the programmed PIC and the documentation for £6.

I will also be at Norwich and Haydock Park if you want to have a chat and demo.

David

Just an update on the AMS piston tank controller project from the recent meeting at Norwich.

If you saw my R7 and Resurgam working at Norwich then you were looking at 2 of my home made piston tanks with the AMS software in action.

This video shows a dive/surface cycle with R7.

https://www.youtube.com/watch?v=fWcAFKaEmZ0&feature=c4-overview&list=UUdTPmv21X_wj_fvIzJtMzQg

This one shows the R7 unit working on the bench.

https://www.youtube.com/watch?v=ghnEjBj04B0

For those of you have already purchased the software and PIC with instructions (£6 to members incl. £1 donation to RNLI) we would appreciate comments here, on how you are getting on with the development project. (We can give you free updates of the software if you return the original PIC)

David

Just a couple of follow up videos showing AMS PICs controlling a pumped pressure system for Richard, this time. The servo operated pinch valve is also activated by the PIC. (You don't need to use this option Richard - just don't plug a servo in.)

The first one shows the use of the standard H bridge board:

https://www.youtube.com/watch?v=egE07WmI_jM

This one is using a much simpler and cheaper approach (no etched PCB and only 3 components:

https://www.youtube.com/watch?v=I6vVdhTdutQ

And yes Richard these are yours for evaluation etc. (Will get them posted soon!)

David

They work really well, David, many thanks indeed. Looking forward to seeing mine installed in the Skipjack.

Final video in the series. The new, much simpler, cheaper H bridge board.(This one has just been posted to Nigel.)

https://www.youtube.com/watch?v=_yASZMTGn48&feature=c4-overview&list=UUdTPmv21X_wj_fvIzJtMzQg

David

That works very well, David...very impressive.

Thank you!

I posted your boards at the same time, Richard.

David

Great, thanks David...much appreciated.

My boards have just arrived David...and proper written instructions too!

Thanks again, much appreciated.


Richard

We have just uploaded the full instructions for the proportional piston tank controller board to our new AMS website. This includes the PCB details, component list and software.

It is in the "Files" section of the new website.

http://associationofmodelsubmariners.com/pages/software.html

A basic description of the controller:

- Proportional means that a stick movement produces a proportional movement of the piston in the tank.

The electronics to proportionally control a piston tank needs to have the following parts:
- A method of counting the revolutions of the screw thread which drives the tank. (A Hall effect sensor, in this case.)

- A microprocessor (In this case a PIC) to process the receiver output and remember the number of screw thread revolutions and to control the motor control board (The H bridge.) The software includes proportional and derivative control functions. The counter can be reset by powering off the TX. The software includes lost signal routines.

- The H bridge is a driver chip and 4 MOSFET transistors which control the piston tank drive motor in forward and reverse. The H bridge is to a Microchip design and includes the protection suggested by John R (Electrolytic capacitors fed by Schottky diodes to prevent any problems with current surges.)

-Limit switches are needed to provide security against any drive overruns. I favour a completely independent circuit using microswitches with diodes to allow reverse. (See Norbert Bruggen's schematics in "Model Submarine Technology) In normal operation only one microswitch is triggered and this only on first power up.

The design is very reliable and I have used this every 2 weeks or so in one of my 3 submarines for the last 4 years with 3 different tanks. I have used it with both 40Mhz and 433/458 Mhz r/c equipment (As developed by Tim Senecal). It works with both but the lack of interference on 458 makes the piston tank work more smoothly.

We have made the software available under an open license for people to use and modify as they wish on the basis that their software continues to be available to others. So it is not for commercial gain.

The software is written in assembler for a PIC micro.

An Arduino version written in C would be very welcome!

The mechanical construction of piston tanks is covered elsewhere in this Forum but some tips include:

- threaded M5 stainless rod works well and matches the "screw turn data" from the controller.

- don't try to move the piston too quickly - current draw and electrical surge problems. I use gearbox ratios of about 1:30.

- the magnets for Hall effect sensors have a habit of flying off and sticking to steel items! They can be attached to suitable gear wheels etc using hot melt adhesive.

Have fun with the design and I hope you find it useful and please say how you have used it and suggest (and make public) any software improvements.

David