knock sensor question

[tberk@mindspring.com (T Berk)]

Chris Boggs wrote:
> 
> Does anybody know how the knock sensor works?  Is it just an
> accelerometer set to a characteristic knock frequency?  Because I was
> thinking of making a type of home made data acquisition system for my
> VW. It would be interesting to see under what conditions predetonation
> would occur.  As well other types of engine things. And would probably
> help in fine tunning.
> 
> Chris
> 87 16v
> 



It's my understanding it's a tuned michrophone.

TBerk