Reeduino PPM encoder - up to 12 channel Reeds

[David Holland 2]

Hello, Phil.

 

Well, after following the Reeduino reed encoder thread on modezero I have spent today soldering wires, resistors, switches and stuff and the results are in the picture below. A final couple of questions, if I may? Do I still do the Schottky diode mod if not using the NRF24L01 board, what do I do with the Aux channel output (channels 11 & 12?) if not using it and what “Sketch” do I need to programme the DIY MORE. I have a USBASP thingy which I presume connects from the USB on a computer to pins on the DIY MORE? Apologies for my ignorance, the mechanical bit is no problem but the electronics are a very firmly closed book to me and I know only too well how difficult it is to get the magic smoke back into all the little components on the PCB.

[Phil Green]

Hi David, ideally I'd always suggest getting the files from http://www.singlechannel.co.uk as thats my own repository (the 'Archive' page) and forum posts soon become out-of-date.

Item P18 is the current (2022) Reeduino sketch and item P19 is the matching document, hopefully this is what you used.

The sketch should be loaded using a usbasp rather than via serial, the document explains why.

The 'schottky mod' is just a convenient way of connecting the RF module by repurposing a redundant 5v pin for a switched-battery connection to the module.  

There is a row of six pins, of which we use three for neg, pos, and PPM to the RF module.  PPM is generated on D0 which conveniently appears on this header as 'rxd', and GND is already provided, so we have the three pins needed by the RF module. Electrically the module can be connected in other ways but this is very convenient as it can be plugged & unplugged via an ordinary twisted servo lead. 

 

If you dont want the aux channel, choose the 10ch option in the Toggles configuration (D2/D3 on the left of the diagram) (again, its all in the doc...)

 

 

 

*** I noticed that you seem to have several switches & buttons short-circuiting the pos and neg.... switched options use neg and signal (black & yellow header pins)

 

 

Cheers
Phil

 

 

[David Holland 2]

Thanks, Phil, good spot. Told you I shouldn’t be allowed out on my own.

[Phil Green]

I could almost smell the smoke from here 🙂   

[David Holland 2]

Phil (in a whiney voice), I am still struggling with my reeds Tx. A knowledgeable club mate has programmed the Arduino for me and I am using a Spectrum Tx module but I cannot get the Tx to bind to a receiver. As I said, I have successfully built the single channel Tx and I have tried binding the new  Tx module in that (both modules are the same) without a problem and I have tried the module from the S/C set in the reeds Tx still without success. I have run out of ideas, do you have any?

 

David

[Phil Green]

Hi David, does the encoder beep "dah di dah" when you switch on?

(make sure its a DC buzzer, not a 'piezo' - DC buzzer will sound on a rx battery)

This at least confirms the processor is running and the program is loaded.

Any LEDs showing?

Do you have any means of displaying PPM? a scope or a PPM meter?

What type of Spektrum module do you have? the DM8 & 9 for example have particular PPM requirements and need upside-down PPM.

Is it wired exactly to the Reeduino document or have any changes been made?

Did you power it up (even briefly) with those previously noted short-circuits?  😄

Cheers

Phil

 

Edited February 21 by Phil Green

[Phil Green]

I took the right-way-up/upside-down PPM option out, it was redundant cos modern modules dont need it, but if your RF module is an old Spekky DM8 or a DM9 then there are a couple of necessary configuration changes.  Then you'll need to ask your clubmate to reprogram the board. After reprogramming it should drive a DM8 or 9 module just fine.

 

At the beginning of the sketch, immediately after the comments, the second define needs changing from:
#define onState 1  //set polarity of the pulses: 1 is positive, 0 is negative
to:
#define onState 0  //set polarity of the pulses: 1 is positive, 0 is negative

 

and the sixth define needs changing from:
#define PPM_PulseLen 300  //set the pulse length
to:
#define PPM_PulseLen 400  //set the pulse length

 

[David Holland 2]

Phil, in order of your questions :-

 

No sound at switch on.

It is a DC buzzer, sounds when Rx battery connected.

No LEDs on Arduino but are on Spectrum module.

I don't have a scope but my clubmate (Ron) does. The Arduino showed outputs on his scope when he returned it to me after programming.

The module is LemonRx DSMX/DMS2 compatible model no. DSMPSDRH001 (LM0080).

It is wired as per the "12 channel reed encoder "Reeduino" with S/C emulation - 2022 update" notes from ModeZero with no changes.

I took the assembled Tx to the club and asked Ron to check my connections before powering it up.

 

The Lemon module has a standard servo type gnd, pos, sig output pins connected to the gnd, 5v, rxd pins on the Arduino.

I'm using a 2s lipo for power.

 

TIA

 

David

[Max Z]

2 hours ago, Phil Green said:

I took the right-way-up/upside-down PPM option out, it was redundant cos modern modules dont need it

Hi Phil, some still do. I have recently built a transmitter (to operate a model train) using a FlySky RM003 module which is still available on the internet, and it definitely requires an upside-down PPM stream, i.e. 1-2 millisecond pulses positive and mark pulses to GND. Like we found out some years ago when I was building a SC (mimicking)Tx.

 

Cheers,

Max.

Edited February 21 by Max Z

[Phil Green]

Hi again. if it doesnt light up or beep it seems likely theres no power.  Are you seeing 5v across the header pos & negs?

Was it powered up with the shorts previously mentioned?

Is this a board I supplied David? if not have you done the mod to provide power to the module header? Its not done in the photo  (though that wouldnt stop the encoder powering up so long as the mod is done correctly)

BTW the Lemon is happy with either ppm polarity but thats not the problem as its not getting that far. It sounds like power to me,

unplug everything, power up the encoder alone and check you have 5v on the headers first please and we'll go from there 😉

 

 

 

Power mod:

 

https://youtu.be/gG0DzR_McWQ?si=Wql91Y8u1WrRQDX2

 

Edited February 21 by Phil Green

[Phil Green]

Edit window timed out!

Without the power mod that 5v pin on the module header is a 5v input so the module wont get any power.  If you prefer not to do the mod, if its too fiddly, just separate the module pos and take it directly to switched battery pos.  All the mod does is to route switched battery pos to the 3-pin header for convenience 😃    

But thats by the bye if the encoder isnt powering up 😁

Edited February 22 by Phil Green

[Phil Green]

19 hours ago, Max Z said:

Hi Phil, some still do.

 Thanks Max I had to economise on inputs so dropped polarity as a hardware-switchable option, its still there as a software switch, my thinking being that for example a Flysky flyer will probably be sticking with Flysky so its not an option you'd need to change on the fly. With any encoders I send out I always ask which RF module will be used, most recently someone wanted one for use with an internal FASST board from a T6, the most awkward of all with power level and failsafe being 'hidden' in the PPM pulse widths 😏

[David Holland 2]

Whey hey, Phil. It works!! I would never have got there without clubmate Ron’s help, he spotted that I had fitted 10 ohm resistors instead of 10k. Going to try it in my Super 60, should be a suitable test bed. I’m told flying reeds is harder than you would think.

Thanks for your advice, we got there in the end.

 

[Phil Green]

Well done David, perseverance pays off.

I wouldnt say its harder its just a bit different.  Pulse the controls for smoother turns rather than holding them. 

I like flying reeds, gliders and powered  -  though I seldom fly power now, I've a Tauri and a J60 both on reeds.

Good luck & let us know how you get on 😉

Cheers

Phil

[David Holland 2]

Well that was a successful morning. Three flights with the Super 60 and it is still in one piece. Ran out of aileron trim and needs more downthrust  but quite manageable. Raised a few eyebrows amongst our newer members who couldn’t quite get their heads round the logic of forsaking the joys of modern propo for such an archaic way of controlling a model aeroplane, however the more “mature” nodding sagely with a hint of nostalgia in their eyes.

I fly mode 1 (shouts of “dinosaur”) and the layout of elevator and aileron on the top row of toggles and throttle below aileron with rudder to the left felt very natural. A glide approach seemed to work for me allowing elevator and aileron to be jiggled for half decent arrivals.

Many thanks to Phil Green for making this stuff accessible to us mere mortals and his help and advice during the build.

[Phil Green]

Excellent very well done David, its easy isnt it? 😉    Honestly your post has made my day!

But now you have a problem... because retro R/C is addictive! One set is not enough!

 

Any photos of your reeds foray?

 

Cheers

Phil

[David Holland 2]

It was not as difficult as I thought it would be, Phil, in fact I found it quite natural, even flying a slightly out of trim model. Can't wait to have another go.

I have built the single channel set and flown it in a Matador but a Black Magic would be more suitable and is next for the building board.

I think I said before that one of the joys of this hobby is the endless list of new things to try and the satisfaction when one achieves a modicum of success. I was too busy containing a puckered sphincter to get photos but I'll try to get one of the guys to take a couple next time I fly.

 

David

[David Holland 2]

Weather here (Northamptonshire) has been rubbish over the past couple of weeks but today was lovely, very light wind and not too cold so I got in a couple more flights on my reeds equipped Super 60. Flew beautifully and I really enjoyed it. I wonder, Phil, if there is any facility for setting a timer on the Arduino, couldn’t find any reference in the 2022 update. Not a problem as there are plenty of cheap timers available but would be nice if there is one built in.

 

David

[Phil Green]

Sorry, the propo encoders do but theres no timer on the Reeduino.... but I'll put it on the list 🙂

I'm really pleased to hear that you're enjoying this time-warp back to the reeds days!

[David Holland 2]

Thanks, Phil, I’ve ordered one that bleeps when time is up from Amazon. Forecast for tomorrow is good again so planning another couple of sorties. Do you have any suggestions for a 70’s aerobatic airframe as a follow on from the Super 60?
 

David

[Phil Green]

The ultimate would have to be the Taurus I think!

There are intermediate reed models too such as the Smog Hog and Tauri, also the Keil Kraft Fleetwing & Student.  Though I've mostly been a sloper since I was a kid 🎂