I've done a lot of searching, but haven't quite figured this one out.
I am working on building a datalogger for my car, step 1 is to record engine rpm. My car has a GM HEI distributor that has a tach output. This output produces a 0-12v signal, the frequency of which changes as engine rpm increases. I've read that when the ignition coil field collapses, this signal could see a spike of a couple hundred volts.
What's the best way to regulate the signal voltage down to 5v and protect it from large spikes? I don't care about measuring the voltage, I just need it to cause a pin to go high.
I have a very basic understanding of circuits, so being very detailed about what components would work, why, and a general idea of how to set up the circuit would he super helpful! Sorry if I'm asking too much.