"sensorless" cycle detection

[simonjamain]

Objective: The mosfet can detect cycles without sensing the movement of parts

ideas

Based on the fact that the motor power draw fluctuate according to spring compressions, we mays be able to detect cycles by monitoring the current.

Note: monitoring the voltage can be enough as it usually drops with power draw.

Here is a test i made using a current and voltage sensor during airsoft replica cycles (with 8.4 nimh or 7.4 lipo I don't remember)

(blue: current, red: smoothed average, yellow: voltage)

how could we detect cycles ?

We could do spike detection.

We could also used the slope of the current curve.

and all of this need adequate smoothing

Resources

http://coertvonk.com/sw/embedded/arduino-pitch-detector-13252/6

sketch (probably) used to produce the graph currentsensor.ino.txt