http://www.autometer.com/tech_faq_answer.aspx?sid=3&qid=13This sounds like a viable option, but the signal to the cluster tach is not the same signal as what our tach needs to see (12v square wave).
I was figuring I could just feed a signal into it but I am not sure what type of signal I would need to use?
Analog rev counters are usually frequency meters driven by the 12V square wave off the coil -
I'm looking for a bit of advice... I'm wanting to control an aftermarket analog automotive tachometer with an arduino. I was figuring I could just feed a signal into it but I am not sure what type of signal I would need to use? Is there a standard for this?
Note however that the signal on the negative coil terminal is a complex waveform that looks nothing like a 12V square wave.