Cool Motor Encoders

SouLJah

Hey I have a motor encoder connected to the javelin, the motor encoder provides a square wave with frequency corresponding to the speed of the motor, can anyone tell me how to accurately measure the frequency of the square wave?

Thanks

Peter Verkaik

You can try doing 2 CPU.pulseIn(), one for a low pulse and one for a high pulse.
Add the 2 results together to get the timeperiod in 8.68 usec units.
Then F = 1/T = 1 / (count*8.68usec) = 57600 / (count/2) = 28800 / (count/4)
so F = 28800 / (count >>> 2)
Edit:
if you know the squarewave always has a 50% dutycycle, you can do with
just one CPU.pulseIn() and use
F = 28800 / (count >>> 1)

regards peter