has anyone taken the square wave tach signal and converted it to an anolog?

[Qualitywires.com]

I am looking to turn the square wave signal of my tach (Tap into it with a wire and make the square signal into a wave or anolog signal....I need that analog signal for my Aeromotive electric fuel pump controller.

Anyone?

 

[joe117]

A square wave is an analog signal.
The frequency of the square wave changes as the engine turns faster.
You want a DC voltage that varies with the frequency of the square wave, right?


I believe that it wouldn't be too hard to design a circuit that would do what you want.

Have the incoming square wave charge a capacitor with a resistor across it.
The faster the tach pulses come, the less time the capacitor has to leak down.
This will give the frequency to voltage signal you want.
The voltage level on the cap would be hooked to one side of an op amp. the output of the op amp could be adjusted to give the voltage level range for the frequency range of the square wave.

There is an IC chip that I have used to do this kind of thing. It's a 9400. Radio Shack used to sell it under stock number 276-1790.

You are going to have to get someone to design this for you. Anyone who tinkers with IC circuits should be able to do it.
I don't have any access to a lab so I can't do it. There's probably someone on here who can.