Electronic Trip meter

Hey All

I am building a electronic trip meter using the ic mm74c925 and displaying the output on a 7 segment LED display. Im looking for a counting circuit that counts the rotating driveshaft waveform {which is sensed by a reed relay} upto a preset value on a dip switch and then resets automaticly and outputs a high signal.

Any help would be much appreciatated

cheers Newelectroman

A reed switch is too slow. search this forum for speedometers and tachometers.

im using the reed switch because it will output a nice square wave form that can be counted by the counting circuit.

just check for switch bounce on the reed switches

yep I am using a schmit trigger circuit to fix that