PINNED - Plug & Play PGDT for Radio Control

[woodygb]

The difference must be that the Omni is expecting the reference pin to be at about 6v? And a matching 6v centre on the "swing" voltage.

It could well be ....makes things a little more of a PITA but still possible.

Any chance of giving the Omni's pins 1,2 & 3 a 6v supply and seeing if it will start up?

[Burgerman]

It does, that's what my old 35mhz box is doing.


Should I post everything, so you can take a better look? And test?

[woodygb]

Feel free to do so if you wish B.M.

OR

return the interfaces and I'll rebuild / modify and resend.

[Burgerman]

Guesswork seldom works as planned. I will send cable, pilot plus, Omni, both your interfaces...

If it can be made neatly to work with the Omni plus, it will work with the other Omni for the now common r-net too, and likely a bunch of other controllers. So will be useful to many. I get a lot of emails about RC chairs. For loading into cars etc.

[Dreamsdadman]

So woody I kinda skipped through the pages as it seems it got off track for different controllers. I have a PG square box quickie joystick that I need R/C. I have all the spektum equipment as I fly airplanes. Do you have a working model to sell for that my application?

[woodygb]

I'm fairly confident that I can interface to your pod ..BUT ... to be absolutely sure I'd really need access to a pod that is the same or similar.

Is it similar to a Pilot+ pod?

[woodygb]

I've just been looking at your posts in the Quickie brakes thread .... are you wanting to R/C a Wheelchair with a rider or are you repurposing the Quickie for something else?

[Dreamsdadman]

I am trying to make a stage prop platform 4x8 for a local theater group go on and off stage for a scene by itself. I just need it to move 30 feet turnaround and go back real slow. Like 1/2 mph. There may be someone sitting on the platform.

[woodygb]

I'd need to find about the joystick pod that you have... is it the same or similar to the Pilot+?

[woodygb]

I assume that you can use a multimeter and aren't averse to probing around inside the pod?

If so Email me nala_doow@hotmail dot com and we can investigate your pod.

[Burgerman]

pick up Monday morning, 24/48 hours, Yodel...

Pilot plus, cable, Omni plus, 2x RC interfaces.

[woodygb]

Cheers John,

Have I permission to poke around inside the PILOT+ Joystick?

[Burgerman]

No joystick sent. Not needed.

Its pilot plus OR joystick. Goes on the end of the same wire...

If you want one to poke about in I can send one?

If you reply asap I can unseal the box and cram one in!

Or post later.



Regards
The collection of particles known as Burgerman.

Added... Since I just arrived back from the pub I will try and unzip the package, and get one in.

[woodygb]

Thnx ..most helpful

[Burgerman]

Just put a brand new basic one in, but with non standard handle. Its a rubber one, for a quad that has grip issues, home made.

You should be able to figure out how to make your device work on the stock pod as well as the pilot plus.

[woodygb]

Parcel arrived 5.30 pm .

I'm happy to report that the non flashing interface is now flashing away merrily...
During your voltage divider mod you managed to break one of the GND wires and one joystick output... easy fix ...BTW the voltage divider works fine outputting the intended 2.5v .

[Burgerman]

Great. Told you my eyes don't work...

But. Does it work the Omni? I suspect that needs a 6v centre point rather than the 2.5v... ?

If you hold down "mode" (I think) on strartup, it allows you to calibrate a centre and throws accurately. As long as you have a (almost) 6v reference. At least that's what my existing 14 year old 35mhz interface does and it still works.

[woodygb]

Still seeing if I can use the existing digipot to output the 6v centre and 1.2v-1.3v swing... the spec sheet suggests that I may not be able to use it.

I'll play around tomorrow.

[Burgerman]

Is there no way to raise its whole 5v / 0v system "up" to the centre of the 12v / 0v supply?

I mean like use a 4v regulator, call that 0v for your device. And add a 9v regulator for your 5v rail? So you have:

0v 4v
0v 9v
0v 12v (existing supply)

Then run your device from the 4v and 9v? Then program for a 6v centre reference? (2v neutral position)

Or symmetrically with adjustable inverters. So 3.5v and 8.5v leaving 3.5 left over...

[woodygb]

I had hoped that adding a pair of resistors to my digipot thus would do the job.

res-omni.png (8.45 KiB) Viewed 15360 times

Seems that the digipot doesn't like the voltage differences that are now present between various pins.

Absolute Maximum Ratings †
Voltage on VDD with respect to VSS ............... -0.6V to +7.0V
Voltage on CS, SCK, SDI, SDI/SDO, WP, and
SHDN with respect to VSS ...................................... -0.6V to 12.5V
Voltage on all other pins (PxA, PxW, PxB, and
SDO) with respect to VSS ............................ -0.3V to VDD + 0.3V

[woodygb]

I have had the Omni working ..and had it calibrate to the interface .

It complained on the first couple of calibration attempts ..then I remembered that I had to reverse the Ele channel .. the Omni was then happy with the Forward signal ..bizarrely the Steering channel will ...ATM ...only calibrate if I reverse the stick direction .....Left is Right and Right is Left despite reversing the Aile channel signal.

That minor problem is something that I'll look into later.

[Burgerman]

You mean left is right even if you reverse the channel? Or it will only calibrate that way?

Maybe its reversed in the pilot plus box you have, in its programming?

Or your transmitter neutral isn't very accurate? Those spectrum sets are a bit "Chinese" if you know what I mean...

[woodygb]

It only calibrated that way .

It seems to be all sorted now ..... it appears to have been a minor whoops! in my re programming of the Arduino's digipot steps...

Some more "playing" to be sure everything is as it should be ...then a tidy up as it's a little bit of a rats nest and I'm unhappy with the fit of some of the push on plugs ...I may just solder them on once I'm satisfied that it's working properly.

[Burgerman]

Servo leads are better. They fit tighter on the rx pins. But those other connectors do work.

So all set to go into mass production?
That will work for the Rnet Omni too...

[woodygb]

I hope to make a few and sell them for a small profit once this one has survived some rigorous testing.

[rustyjames]

Sounds good Woody, looking forward to purchasing one!

[Burgerman]

How likely is say a runaway, with your interface?

Say a coding error?
Crash due to noise/heat/other mechanical thing like gamma ray zapping a memory transistor...
Error due to volts, un-thought of mismatch on failsafe?

Out of 100...

[woodygb]

I've spent months on the code and I'm 99% confident that it's correct and more importantly safe ... the error yesterday was due to a software scale change that had to be made to accommodate the new step count of the Digipot ... I simply missed altering one of the end points correctly on the Steering channel and this resulted in an out of range failsafe condition at the very end of the stick throw that caused the digipot to output neutral.

Heat ...there doesn't appear to be any that I can detect and I've left the assembly soaking for 12 hours at a stretch.
Months ago I did manage to kill a digipot whilst playing by inadvertently exceeding the mA draw on the wipers output ... in that instance the chip got HOT !!

To the best of my ability I believe that I covered mechanical failures ... it should either failsafe or simply not work.

I certainly cannot be sure about the Arduino and or Digipot failure modes as I'm not an expert in all things electronic.

[LROBBINS]

Woody,

I know it's a PITA to do, but you might consider changing the brown out protection fuse of the Arduino's processor. The Arduino bootloader has it set for a fairly low voltage so that people can run it at either 5V or 3.3V (with the clock slowed down), but that means that if you are running it at 5V and voltage drops its memory can get corrupted. I did have this happen once, and it completely took out the bootloader and the board became unusable until I re-burned it. If you raise the brown out voltage, the processor will do a reset or shut off (depending on how some other fuses are set) rather than be damaged. The DC-DC converter should have a pretty stable output, so this is a bit like wearing both belt and suspenders. BTW: "fuse" here has nothing to do with a "fuse" that opens a circuit when too much current is drawn. It is a low-level firmware setting that determines how a processor behaves in some defined circumstance.

Best source I've for such low-level programming matters is http://www.gammon.com.au/forum/index.php?bbtopic_id=123, though you would have to hunt around there to find what's most appropriate for what you want to do - Nick Gammon has written ingenious stuff to really make the Atmega processors "dance", but there are similarly named posts that discuss doing either specific things or very general things so patience and careful reading is needed. He also has an excellent and very complete discussion of power saving/sleep modes. I do recall some thread on the Arduino forums specifically dealing with the brownout fuses, but finding things there can take a lot of perseverance.

Ciao,
Lenny

[woodygb]

Cheers Lenny,

This memory loss causes no other problems than causing the Arduino to cease functioning?