From another thread....
Here
Thanks for the help AudioGuru.
Ok, I got the output I needed, actually I have the output I need two different ways, using two different circuits, and I am still trying to figure out which one to go with.
Either way, now that I have a way to activate a comparator, or 555 timer, I was wondering which way would be the best in order to get a square wave ttl pulse out, that can be read by a pic uController?
I was thinking I could use a 555 timer to produce 1 square wave TTL pulse (by using monostable mode) every time it was activated by a comparator from the audio signal. However, wouldn't I need to reset the 555 timer every time?
Any ideas as to the best way to get a square TTL pulse out, every time I picked up an audio pulse in, that would be suitable as an input into a PIC uController?
This is one circuit I am using: **broken link removed**
Or, I am just going to use an lm741 op amp, with a 2222a transistor pre-amp connected to the mic.
Either way gives me decent amplification, I am just trying to figure out the best way to generate a square wave pulse out, for every audio pulse that I receive in, to the circuits shown above.
Thanks for your time.