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Nikkilae / PPM-reader

An interrupt based PPM signal reader for Arduino
GNU General Public License v3.0
77 stars 44 forks source link

FIX made microsAtLastPulse volatile ; NEW added failsafe procedure in latestValidChannelValue() #10

Open dantiel opened 3 years ago

dantiel commented 3 years ago

this PR fixes a bug which caused noise in the signal and adds an (opinionated) failsafe procedure.

dimag0g commented 3 years ago

I think 10 seconds is way too much for failsafe timeout, in many cases your model will simply crash within that time. A typical comm loop frequency is 50 Hz, and I would say >10 missed frames in a row warrant a failsafe, so 0.2s, 0.5s or 1s timeouts make more sense.

dantiel commented 3 years ago

ok, i let the decision to the maintainer of the repo. i agree 1 second is probably a better timeout, but 10s seemed more failsafe to avoid false positives when turning off the motor would result in a crash. i used the failsafe preferably to prevent my model flying away, which has happened already by a loose receiver cable.

dimag0g commented 3 years ago

@dantiel The failsafe coming from PPM should in my opinion be the equivalent of "stage 1" in betaflight terms, when the drone simply stops getting further away uncontrollably (if possible). What you're talking about is the equivalent of "stage 2" failsafe, when the drone soft-crashes or tries to get back using GPS, and for which 10 s (or even more) sounds appropriate. I assumed that the comm library should implement only "stage 1" kind of functionality.