PISTON TANK DRIVE BOARD

HI DAVID
Thought i would post this on hear under electronics, have finished doing art work for double sided PCB board for ballast tank control unit, have fitted all mods on to art work i think i will do one board first to see how it turns out. If that works out OK will do some more boards. Didn't bother putting resistor on pin 2 receiver in put on pic as i didn't think it was worth it hopefully it will work out OK could make this a lot smaller if we went in to SMD components but if some body in the club wont's to make it most people don't won't to get in to soldering SMD components as they are quite small, some of these can be as small as a grain of sand

ALL THE BEST JOHN

you got all that rich

Thanks John!

This is referring to the idea of making a PCB board for members based on the articles in our magazine a few issues back.

More news on this soon.

David

John has now made a number of etched boards and they are working well, I understand.

He has worked his personal magic on them and they are double sided (so no wire links!)etc.

We will have a few of these boards available to members at about £10 each (Proceeds to the AMS and our Charity the RNLI)

This means that with the addition of the Piston Controller PIC chip (£5 to AMS members only) and some other components (Perhaps a further £20) you will have a proportional piston tank controller.(The same H bridge board can be used to control a pumped tank system with a different PIC)

This is still only suitable for someone with some knowledge and enthusiasm for electronics.

It would help us if you would indicate on here if you would be interested in one of the boards. (AMS members only. First mention, first served!)

David

HI David
Just thought i would do a quick reply, left circuit board running for a few hours last night and all seems to work fine, circuit board has got all the new modifications and all so has got jumpers for changing settings on pic
All the best John

That's good to hear, John.

By way of explanation, the jumpers control the drive screw length and also an alarm input which produces a "pump out" from a low battery voltage or perhaps a pressure switch signal - over depth etc.

It also worth mentioning that if you use the H board with the pump control PIC, this controls the pump (pump in and pump out) and also a servo which is moved through 90 degrees to operate a (pinch?) valve. This eliminates micro switches and means that you can pump out as well as in.

I would like to buy a board, how do I register interest

Just like that, Dain. Many thanks!
John is posting them on to me in the next few days and one of them is reserved for you.

Not exactly an overwhelming response, so far!

I've sent you an email, Dain.

David

I am interested, but I am not a member (yet). Working on saving up a few $$ to subscribe!

Thanks for the interest!

It is only £12 a year for membership (Just less than $20).

We need a reasonable level of interest because making boards has a fixed cost.

The more we make the cheaper it gets for our members!

(And we want to keep it to members because we don't want to interfere with commercial suppliers. Think of it like Harrison Ford building an Amish barn in "Witness"!! I can just see Nigel and John in straw hats.)

David

Thanks for the comments and queries. Some answers:

To Marius - Piston tanks can be controlled in 2 ways:

- Simply switched between the limit switches (Stick movement gives direction only i.e not proportional)
- Proportional control (Stick movement produces a proportional movement of 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 H bridge is a driver chip and 4 MOSFET transistors which control the piston tank drive motor in forward and reverse.
- Limit switches are needed to provide security against any drive overruns.

To Dain - Many thanks for your suggestions and it would seem that a drilled PCB (i.e no components on it would be best for you.) I will write more fully to your PM now.

Many thanks for everyones continuuing interest in this collaborative project.

David

THANK YOU @david f,
Now I get it!.It wheel be more economic to produce as many is required and You want to know if are Requests "on market"!.
MARIUS

You have "Got it in one.", Marius!

Interestingly the last set of boards I had made by Olimex in Bulgaria. A very nice job they did for not too much money.

Not too far from you, I think!

David

I live at only 120-130KM by BULGARIAN border!!!.lol.
MARIUS

Walking distance then,!!!!

Man I'm NOT a GLOBE TROTER or at least ATHLETE so NO WAY Walking!!!.
Post Office is Perfect for Me!.
MARIUS

WHERE'S YOUR SPIRIT OF ADVENTURE!!!!

Yesterday I tested the pump control software with the new no-signal and low voltage failsafe. Worked very nicely in ORP Dzik. (Witnessed by Dave J)

This software is on the PIC chip (£5 to members) and plugs into the standard "Piston" Drive board. It controls pump in and pump out and has an output for a servo operated pinch valve, avoiding the use of micro switches etc.

David

Just to let everyone know that we are still actively working on this one.

Any more expressions of interest for?

- Bare printed circuit board (About £10)
- Assembled and tested boards.(£40 - 50)

David

Same picture?.I don't recall any?!.
MARIUS

A very good point, Marius!

Here is the one I built using an Olimex board. Quite spacious and easy to build and remember that the same board (with different PIC chip) can control EITHER Piston tanks OR Pump control system with a servo operated valve.

The chips are(from left to right) PIC chip , MOSFET Driver chip and the 4 MOSFETs.


David

A bit of "Market Research" on this one.

The new Engel board (Proportional control using Hall effect sensors) looks quite good and is priced at a pretty reasonable Euros 60. I don't know how well it works. Anyone any experience of one?

Talking with Nigel, it would be difficult for the AMS to compete with this by providing a completely assembled tested board at much less than this.

So no complete board but we are still looking to provide to the PIC chip and the printed circuit board for those who would like to "have a go".

What does anyone think?

David

Well, I have now had a chance to see the new Engel proportional board working "on the bench" (Courtesy of David J who bought 2 at Dortmund.)

It works very smoothly with no glitches. Slight time delay when you send a command. Quite precise - fitted with 4 magnets. Failsafe works well and the software looks good.

David reported a lot of trouble setting up the magnets - they tended to fly off and stick to things when he was trying to glue them!

The English instructions were hard to follow (very densely written.)

So overall looks very good for the price. I don't think we will offer a built board through the AMS for this reason. Just some bits for enthusiasts.

David