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What am i doing wrong? Reading PPM(???)Futaba Multi-Prop 4+4(8039) with Arduino;

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BogdanM:

Dear all,
I am currently working on my OTW type VII internals and started to play around with Arduino in the process. The first thing to figure out is how to read the receiver signals and PPM stream(???) on Channel 6 coming from the multi-prop
encoder.

1. Reading normal PWM channels is working fine and i have succeeded in controlling a 12v DC motor with a Hbridge that will be used to control my pistons, no issues here.


2. The next normal step was to try to read the Channel 6 where my multi-prop encoder is mapped to the receiver, the reason for doing this is to try to replace the existing Multi-Prop Decoder (F1516) all together and stick to the Arduino for all submarine operations.


I found a very useful tutorial here on how to read a PPM stream(Its a PPM stream?) and started to write the code(here). To my surprise its not working, I only see the first pulse(1 out of 8) with the value of 21976. Its the expected stream coming from receiver Channel 6(Multi-prop 4+4) a PPM?
So channel 6 on the receiver is connected to the digital pin 8 of my Arduino UNO board. What am I doing wrong?

Please also note that when using the decoder in the normal way(no arduino), all the switches and and props are working as expected.

I am using:

1. Robbe Futaba F14 transmitter;
2. Robbe Futaba FP-R118F receiver;
3. Futaba Multiprop 4+4(8039)
4. Arduino UNO R3;

More images here.

You help is most welcome, i have no other idea how to resolve it.

Thank you. Bogdan

C-3PO:
Hi Bogdan,

I have not looked in deail at your code - the value of near 22000 (ms?) is remarkably close to the overall "frame" length - coincidence?

Try the link below to read your ppm stream

https://github.com/Nikkilae/PPM-reader

and also see Tim Senecal's code

https://www.modelboatmayhem.co.uk/forum/index.php/topic,57119.msg595279.html#msg595279

Regards

C-3PO

BogdanM:
Hi C-3PO,

"https://github.com/Nikkilae/PPM-reader" library throws me the following error: "Using library PPMRead in folder: C:\Users\Bogdan\Documents\Arduino\libraries\PPMRead (legacy) exit status 1'PPMReader' does not name a type", seems related to some legacy timer library.


Instead,  this one "https://github.com/DzikuVx/PPMReader" gives promising results, the example provided does not return the exact values per channels but I will figure out.

Does anyone knows how to code the radio failsafe?

Thank you one again C-3PO.

Regards,

Bogdan

C-3PO:
I use the ppmreader by Nikkilae without errors!

I think it's probable that it may be how the library files are installed as you would have copied them from the zip file rather than being able to install via the IDE menu (does not work)

PPM-reader-master.zip/ppm-reader-master/PPMReader/

All you want from the github zip file is the ppmReader directory & it's 2 files manually copied into your library directory

The error "does not name a type" suggests  the library has been installed in a nested directory  arduino/libraries/ppm-reader-master/ppmreader/*.* rather than arduino/libraries/ppmReader/*.*

See this article - https://forum.arduino.cc/index.php?topic=155921.0

But as with all things Arduino it could be one of many reasons :)

Failsafe
I have various sets of code for failsafe situations - have you defined the "cirumstances" that would trigger your failsafe?

Regards
C-3PO

tsenecal:
the robbe multi-prop and multi-switch devices DO NOT output ppm, they output a simple pwm stream that is time-sliced.  there should be 8 normal length pwm values, followed by a ninth "sync" signal that is "outside" "normal" ppm values...  ie 1500ms 1500ms 1500ms 1500ms 1500ms 1500ms 1500ms 1500ms 550ms  where the 550ms is not used, but indicates the end of the usable values.   also note... if the channel on your transmitter is reversed, the 550ms sync signal will be something more like 2350ms

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