I'm thinking about a small audio/visual project, of extreme simplicity but very scaleable. Basically all I want to do is use a small cheap 8 pin micro controller, microphone, LED, and coin cell to create tiny little sound sensative LED, thing is the package needs to be small, I don't want them larger than the size of a quarter, preferably a dime. Price is also a problem as I'd like to build perhaps 100 of them at least that's my goal. I'll start off with one which is easy and cheap enough and see what happens when I scale up to 10. Price is the real problem though, I can't seem to find any compact microphones that would fit the bill and still be cheap enough to eventually buy 100 of. I'm looking for a normal audio frequency responce of 30hz to 20khz and a price as close to a dollar as possible, not finding anything even close to that price range though. Suggestions would appreciated.