Can anyone point towards a circuit that would take an input from a piezo crystal and
create a +5v pulse from it?
I had been trying to do it with a simple op-amp
circuit, with the legs of the piezo inputs connected either side of a 5M pot, with one leg
of the piezo connected to the - input of the op-amp through a 150k resister and also tied
to 0v. The wiper of the pot connected to the + input of the op-amp (also through 150k
resister) thus relying on the theoretical infinite gain of the op-amp to produce the
Supply to the op-amp is +5V and 0V.
Even with no signal
present I am measuring 75mV across the + and - inputs of the op-amp which is enough to
swing the output to +5V.
All I want is a 5 volt pulse, no velocity sensitivity
This is the first circuit I have fiddled with in about 20 years,
so I am definitely rusty on my circuit design! Any help would be appreciated.
(I do know now that I should be rectifying the input from the piezo).