Feature request: Support negative RPM for dynamic harmonic notch

[RickReeser]

Copter 4.5.6

Some specifications allow ESC telemetry to send negative RPM if the motor is spinning backwards (or just clockwise vs. counter-clockwise, as in my case), e.g. DroneCAN esc status message. RPM-tracking notches do not use negative RPM and they will just sit at the minimum frequency:

Suggestion:
I suppose the naive solution of using the absolute value of RPM would suffice?

Platform
[ ] All
[ ] AntennaTracker
[ x ] Copter
[ x ] Plane
[ ] Rover
[ ] Submarine

[andyp1per]

Certainly some judicious fabsf() would probably fix this and would be easy to do.

[andyp1per]

Please can you try

[RickReeser]

Yeah, I will look into it today. I don't have any familiarity with the filtering classes, but I suppose this will be a good introduction.

[andyp1per]

Yeah, I will look into it today. I don't have any familiarity with the filtering classes, but I suppose this will be a good introduction.

Did you see the PR I did?

[RickReeser]

Nope, just saw it. Will try your PR now.