I have started this dedicated thread at the suggestion of another contributor.

This issue has was raised on the main 'Arducopter 2.8 / 2.8.1 released' thread and can be viewed here.


I'm still puzzled by this twitching, however look at the latest log from today and in a little more detail I can see a very small change in the THR IN trace which appears to be directly connected at the time all the motors twitch (see below).

Is the THR IN trace taken straight from the Rx ?

Not only have I done the things as detailed in the main thread, but I have also:

Grounded the aircraft (in case of interference)
Repositioned Rx to top stack
Reprogrammed all ESC

I have attached the latest log.

Would dropping the ESC Update Speed in MP from 490 - 400hz help ?

Any suggestions would be appriciated, in the mean time i am trying to get hold of a duplicate Rx.  Any chance it could be the APM ?

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Yeah OK. I'm almost getting curious now how that has been solved :)

For the future, I guess traditional multiple PWM signal R/C is facing the and compatibility with Futaba SBus, Spektrum's satellite protocol etc. would be more useful to have.

Tell me if there is something I can do for the diagnosis. I have an APM, a 2 channel scope and a '617.



Hi guys,
Here is an except from the LOG throttlein(red) and throttleout (green) (ppm Encoder 2.2.68). With the latest PPM encoder version (2.3.12) I can barely detect spikes.

All Version of PPM Encoder in the zip


Thanks Uwe, but this kind of problem has been reported by me to the dev list for months, well before the release of the older version inside your zip (2.2.64).

Thanks Uwe, I'm currently testing version 2.3.13 and initial results look very good.


Its excellent if you have seen no spikes on 2.3.12 also.


Here is a 10 minute bench test flight, nice smooth traces on all channels (just PITCH IN shown below).


Still need to do 10hrs worth of test flight, but looks good so far :-)

where can i find the Version 2.3.13 of ArduPPM Encoder

Is only for the tester at the moment, a debug version...

Please PM me so that i can send it to you.


I have similar issues as well where I almost crashed my Hexa after updating to 2.81, so far unplugging and plugging the battery to re-initiate my APM2 seem to make the problem go away for me, I also took time to cable tie down my loose wiring. My spikes behavior looks exactly the same from the videos you posted. I'll be keeping a close eye on this thread. 

I am experiencing similar problem. HAL hobby king quad copter.
Thought I would provide an update to all.

I have been testing an evaluation version of the PPM encoder and thanks to the developers the results are very good.

As some may have seen from this and other posts, the problem of twitching has been plaguing me for months ever since I built this, my first Hex.

Despite numerous fault finding exercises including visiting the UK Futaba service centre, I was not having any success. I was just about to replace ESCs nd motors when the Devs thankfully stepped in and rewrote some of the PPM encoder firmware.

Having benched tested the APM for a couple of hours now, I haven't seen any twitches at all on my logs.

It would appear that the twitching issue was unique to Futaba radios and my R6208SB receiver.

Testing will continue and I'm sure once its stability is confirmed, it will be released to the masses.

Big thanks again to the devs, particularly Olivier. Stay tuned :-)

OK I am using Futaba 14MZ on mine if that could help you too !!!!

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