At 17:23 01/18/99 +1100, Steve Ridley wrote:
>I would like to build a circuit to detect whether someone has spoken into a
>microphone. Basically I have a PIC based message recorder and I want to know
>if the user has said anything or not. I think this is called a "voice
>operated switch". The switch needs to generate a logic level that I can
>detect at a PIC input. This circuit does not have meet rigorous standards
>and the less components the better. Any ideas ?

how's an opamp with a diode as a precision rectifier, followed by a RC low
pass, and then into a schmitt trigger input of the pic?

ge