Knock Sensor signal level

[Peter Rueb]

I want to amplify a signal of a knock sensor to feed it to a A/D conv and
later to serial port of a laptop.I kow that frequency varies from 5 - 10kHz
or maybe up to 15KHz.
Can anyone tell me what voltage level i can expect from that little piezo
thing. I doubt that it can be more than +-20mV. I have no access to a scope
and my simple DMM shurely is the wrong tool.
Thanks,
Peter
s68558 at stud-mail.uni-wuerzburg.de