a few seconds on google may give you some help too
http://devices.sapp.org/circuit/piezo/
Probably i would forget the LowPass and impedance buffer stages. Never use it before.
Another idea, that 'could work', is to use a PIC with an internal Comparator. You just need to read the comparator output. I think! Using that, you may implement a software threshold as in some Musical Drums Pad (wich may use those sensor or not...)
Saying that, the sensor impedance may give you some problem.... or not without a 'preamp' or 'buffer' Some bench test will says you all.
Good luck!
PS about the diode... if you use a single rail OP-AMP you'll don't need it. If you use the internal PIC comparator, use a serie resistor and the internal PIC diode may do the job. 1N5817 are still cheap, and almost diode could do the job. It's not as this critical IMHO.
Last edited by mister_e; - 16th April 2006 at 18:59.
Steve
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