Hi Folks,

I use the piezo transducer types (need to be frequency driven) and find a small coil across the transducer works well as these sensors (yes they make good vibration detectors too!!) are capacitive. Some experimentation is required for the value of the coil inductance but these can easily be made.

Note a current limiting resistor is now needed in series to safeguard the PIC pin as the coil basically makes the output a short circuit.

HTH,
Bill