RPM sensor
I put the scope on my Cherry 101301 sensor (& put my glasses on too). It is pretty close to your results. I have the original camshaft position sensor which is an inductive type so I made up a sensor wheel with 4 equal mark/space segments. That should give me the right length pulses, which it did but it was not a proper square wave & the tacho stayed still.
The original pulses from the ECU were a perfect 12V square wave 50% on & 50% off which only varied in frequency. The tacho in these newer VWs are a stepper motor type so I am guessing it was a PWM signal the ECU was outputting to drive the tacho.
I am thinking along the lines of some sort of 555 circuit that outputs the correct 50% duty cycle square wave with the frequency being altered by the Cherry sensor input.
Simple, huh - except I have no idea how to do it.
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