Sunday, 4 January 2009

Reverse is sorted out with a little diode logic :). Speed sensor still not working.

I sorted out reverse with a little diode logic to make my forward / reverse switch work how I want it. The switch is a rotary switch with 3 positions. Forward / Neutral / Reverse.

Start is initiated by turning the key. This provides an interlock so the motor wont start if the switch is knocked accidentally.

I still have some problems with the speed sensor. It is dropping pulses at high RPM. It is a 3kHz unit but something is wrong with it. The max Hz of the sensor should be 4000RPM x 40 teeth on pickup = 2666Hz

See following oscilloscope photos.

Output at 30Hz. Nice and square with a bit of wobble.

Sensor output at 100Hz. Lots of dropped pulses.

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