home brew tachometer

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Original poster: "Metlicka Marc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>

All,
I was just think about tach'ing a motor and wondered if a scope could be
used?
My thinking is that if i stick a small piece of aluminum tape on the
disk, shine a strong pinpoint type light on it, then use a photo diode
or photo resistor or something, couldn't the pulses from the reflective
tape be "counted" with a scope, counter, or even the frequency function
of a dmm?
I would think that "something" could be setup for a tach?
Now for the strobe, Couldn't a simple dimmer circuit like the triggered
gap driver, be used to fire a camera flash lamp?
I would try some of this myself if i didn't already have too many
projects going.
So just some thoughts, comments?
Marc M.