PINNED - Plug & Play PGDT for Radio Control

[Burgerman]

What if they are all a bit different?

So after I fiddle with the "offset" via the RC TX then measure it, it only works for me?

I wonder what the reference is. It may be the CORRECT zero voltage? Or may be a reference FROM the external joystick (so could be connected to a true 2.5v (or 5v?) or whatever your voltage is, from external source. It may also be like the Roboteq either absolute or floating depending on the 12 or 5v rail? So that if voltage changes the neutral doesn't move.

How can we find out?

And what about end points? Will these need a range or travel adjustment?

Need to walk dog, go to the bank. Will have a play when back...

[Burgerman]

http://www.wheelchairdriver.com/pdf-files/omni.pdf

Page 10 may help!

??

[Burgerman]

Where am I getting the 5v from and the ground for the RX because it appears not to do anything if I connect the ground and the 5v wires.

Then it lights up solidly when I connect the servo signal wires. But should flash as its got a bind plug in... The ground appears not to be ground...?

[woodygb]

Where am I getting the 5v from and the ground for the RX because it appears not to do anything if I connect the ground and the 5v wires.

Then it lights up solidly when I connect the servo signal wires. But should flash as its got a bind plug in... The ground appears not to be ground...?

The 5v is supplied from the regulator ..the voltage for this is supplied from the Omni's 12v pins...GND is also via the Omni.

5v wires...plural? ...why plural?

I suppose the question is ...have I wired the DB9 / Omni plug correctly.

[woodygb]

Ah!!! ..Bollux!

If your using the last wire ( modified to show a male plug ) colour diagram that I posted ..IT IS WRONG! ... The numbers and colours are all buggered up.

The one I supplied in the parcel should be correct ... even though it shows an incorrect female DB9.

GREEN is Rudder.... BROWN is GND.... RED is 5v

OMNI%20CONNECTIONS2.png

[Burgerman]

Yep I get that...

Still got a zero problem.

[Burgerman]

RC and calibration etc works. But still get the Omni joystick error. So will now play about with trims till it starts up...

[woodygb]

Drawing showing Male DB9 numbers with correct Colours .

db9 colours.png (26.46 KiB) Viewed 19645 times

[woodygb]

RC and calibration etc works. But still get the Omni joystick error. So will now play about with trims till it starts up...

OK ..Any joy with using the Omni's calibration routine? ... as I believe that the Omni should calibrate itself to the interface " joystick" ( assuming that the outputs are within certain parameters ) ..rather than adjusting the interface "joystick" to suit the Omni.

[woodygb]

If you download the Arduino software... http://arduino.cc/en/main/software#.Uv5M7svivWg ... and install , you could then monitor the data on the P.C. via the supplied USB serial interface and see the inputs and the voltage that is being output... in real time whilst everything is connected up.

arduino monitor.png (40.26 KiB) Viewed 19644 times

[Burgerman]

Will do. Just tried every combination of forwards, back, left, right trim positions possible. It wont start up. Says there's a neutral error or a reference error.

So I am at a loss. Calibrates easily, both LEDs out solidly first time. But I cant get it to start up.

It will not allow me to go to the JOYSTICK CALIBRATION SCREEN. First you need a reasonable zero.

Read section 2 on the Omni PDF. Says the reference pin is the "centre" and all voltages should be compared to that pin. And that the voltages from the joystick should be open circuit, and a 470 Ohm resistor in series.

So I will try to measure the actual voltage on that pin, with reference to ground. I have a feeling its midway between 12v supply and zero so will be about 6v somehow... May be wrong. But the joysticks they use are 12v and 0v so have a 1.2v swing, around 6v point?

Or I can post it al back, and send you the Omni. Do you have a cable, and a pilot plus?

I will take a look later with MY interface, its 12 years since I looked in that box! But its using 35mhz and I no longer have a 35mhs TX here, I gave it to a friend last weekend... So will involve swapping a 2.4ghz rx etc first.

[woodygb]

6v neutral ... that certainly is nowhere near 2.5v!

I did see that the voltage reference was 12v/2 ...but again assumed that neutral would be the "normal" 2.5v .

If that is the case... I'll need to rethink the digipot as the number of steps it has is 257 .... lets call it 256 as it makes division easier.

I could feed it 12v ...this would then give 6v at the center. ... with 6v over 128 steps either side ...so 0.047v per step and I could only use 25 steps .

Hmmm...Is a resolution of 0.047v per step sufficient for decent control ?

I only have a Pilot+ controller ..no cables ...no pod etc etc...

[woodygb]

Feel free to hang on to it till next week and perhaps have a look at the outputs etc via the Arduino software.

If not post it back and update me sometime on the required neutral.

[Burgerman]

I have the reference voltage measured at 5.588v

I dunno why, but I have it held there by 2 resistors. One to the 12v supply, the other to ground. Possibly a precaution. Its just 2x 470k resistors soldered in the D connector. And a wire from here goes to my circuit as well as to pin 3.... For trimming the centre I think.

Ah. I get it now...

Powered up, no plug in Omni free:
Between 12v and ref 3 is 11.602v. Probably floating almost? (remember I have it tied at 5.588v?) Probably meant to be 6... 2 identical resistors in a divider.
Between 0v and reference 3 is just 0.078v So its floating. With a tiny resistance.

So maybe this needs tying at 2.5v for your device to work. Then your signals are above and below reference.

I cant test the actual dc outputs as no transmitter to arm the speed controllers... But I think they are running on 12v... So 6v centre stick.

[Burgerman]

So...

I suspect adding 2 resistors, inside the D connector to hold the reference at 2.5v would fix it.

We have 12v, and 0v so maybe a 1k and a 250k or whatever. A 1k and a trim pot. Joysticks have a reference output... But you used a moulded on connector so I cant do that.

I think ideally your device needs an extra 2.5v reference output wire though to pin 3.

[woodygb]

OK ...

No big problem to replace the current 5v feed going to the digipot by splitting off a feed from the 12v that is currently supplying the 5v regulator.... and replacing the 5v with it.

Then it's just some software fiddling to reduce the number of steps that the digipot will use in response to the R/C pulse.

ARDUINO omni digi.jpg (124.33 KiB) Viewed 19429 times

[Burgerman]

I retyped the above to make it clearer. There in a need only for a 2.5v centre reference to be supplied to pin 3 and it will work. Please re-read!

The pin 3 must be tied to the centre voltage. 12V not needed.

[woodygb]

rereading...

The wires are all present in the DB9 lead ...feel free to strip it back ...find the relevant wire and attach a voltage divider to it.

[Burgerman]

And a 1.2v swing NEEDS a 1.8k series resistor for the correct "swing". From PG drives PDF. The actual swing will be tiny!

[woodygb]

Again... feel free to graft one in if you want.

[Burgerman]

What resistors should I order? Electronics not really my thing!

I thought a 1k and a 470 20 turn for adjustment? And I am not sure my eyes are good enough for this!

I feel sure this is all it requires.

Joystick input is not related to the + 12v or 0v but only to the reference voltage that the JOYSTICK supplies. Now while this is about 6v I think, (12v joystick) I don't see that it will be any different at 2.5v? I hope.

[woodygb]

Should you wish to easily identify the wire colours to pin number.

omni pin color1.png (43.4 KiB) Viewed 19358 times

[Burgerman]

Great!

[woodygb]

What resistors should I order? Electronics not really my thing!

I thought a 1k and a 470 20 turn for adjustment? And I am not sure my eyes are good enough for this!

I feel sure this is all it requires.

Joystick input is not related to the + 12v or 0v but only to the reference voltage that the JOYSTICK supplies. Now while this is about 6v I think, (12v joystick) I don't see that it will be any different at 2.5v? I hope.

Almost any same value pair of resistors over 5k should .. I think ...do the job ...simply wire them as a divider across the 5v output of the regulator.

You could even use A multi turn pot across the 5V regulator output as your voltage divider..... at least temporarily. ..using the wiper as the 2.5v output.

[Burgerman]

I was thinking about the 12v but 5v makes more sense. Trouble is I cant see where to connect. How on earth do you see this stuff??

Its tiny!

Wheres the regulator connections? I consider anything less than 6 gauge electronics... I suppose I can steal it from the rx power supply?

2X 1K resistors? To red wire and prey!

[woodygb]

As an EASY start up test ...you could just take the 2.5v neutral signal from one joystick output channel and jumper it across to pin3 ..the Omni could fire up and the un jumpered channel may work.

Yes ...use the leads supplying power to the RX ..they come from the Regulator ... or take two power leads from the RX to a voltage divider.


How do I see?

22-w-fluorescent-daylight-magnifier-lamp.jpg (8.65 KiB) Viewed 19357 times

[woodygb]

2X 1K resistors? To red wire and prey!

... my electronics isn't much better than yours B.M. ... TRY IT .

[Burgerman]

Tried it.

Pin 3 connected to the centre of two 1k resistors (its all I have, temporarily.

Then connected the other ends to the red and brown rx wires on the board.

Now plug in and:

Nothing... No lights no RX lights...

All correct, no shorts, correct places... Don't get it.

Unless those RC colours don't continue all the way inside past that strange D connector/RX thingy... In which case I have failed.

I will ship you the Omni!

[woodygb]

Can I make the Omni work / function as a stand alone piece of kit?

Is the Omni's pin3 an input ...or is it perhaps an output?

[Burgerman]

It receives the centre point reference voltage that the joysticks put out. Theres a wire marked reference and it reads a fixed half the joystick supply voltage.

The Omni replaces the pod. You will need cable and pilot plus too.

I have them somewhere.