>There is a TONAL VOLTMETER project on the Poptronix website. This would
>give you the basics for the output. Add a clipper and integrator to get a
>linear voltage from the ign. pulses. Hope this helps.

I'm looking for a frequency measuring device (which directly correlates to
RPM) which uses a microphone as the input.  No chain yanking <G>

I need to get an idea of the RPM my boats motors are turning, without
putting something in the boat.

Andy


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Andy Kunz - Statistical Research, Inc. - Westfield, New Jersey USA
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