Electric aircraft motor - GIF

[hemmjo]

It is impossible to judge RPM above a certain level due to aliasing. Aliasing is an inherent problem in discrete sampling of continuous data. Wagon wheels in western movies going backwards indicate negative RPM but we know that is untrue.

The input to our built in audio sensors send very good data to our main processor infer high RPM even with our optical sensors obscured from the data stream. It is difficult to miss the sound of a hot bike screaming out that 10K+ rpm tune cutting through the still night air out in the country. Even to an untrained ear, that is the unmistakable sound of high speed.

I always say a quick prayer when I hear someone going through the gears at max RPM, hoping that sound will keep the deer or some other obstacle from crossing the road in front of the crotch rocket.

[tonyfoale]

The input to our built in audio sensors send very good data to our main processor infer high RPM even with our optical sensors obscured from the data stream. It is difficult to miss the sound of a hot bike screaming out that 10K+ rpm tune cutting through the still night air out in the country. Even to an untrained ear, that is the unmistakable sound of high speed.

Not so much with my audio sensors damaged by excessive exposure to the inputs that you describe.