Hi,

I am currently evaluation different options to be able to recognice a =
buzzer sound from a speaker. For different reasons i would prefer to do =
this with passive electronics only. Does anyone have any experience with =
this kind of problem? It is only one buzzer signal that I need to =
detect. The frequency is unknown at the moment... As an output from the =
passive electronics I would like to have a change in the logic voltage =
level. Since I am really not an expert (by far) on analog electronics I =
have really only found one suggestion that I think might work: Band pass =
the speaker signal at the buzzer frequency and than integrate the signal =
to be able to accept the signal after a certain amount of time.

Regards

Patric Anveg=E5rd

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads