Novice: Audio Activated Circuit

[pcawdron]

I'm a novice, I don't know much about electronics, but I'm enthusiastic and looking to learn....

I'm trying to find an audio activated circuit like one of those whistle key chains where a loud noise activates the circuit. I've taken one a part, but there appears to be some sort of surface mounted small IC covered in black epoxy rather than mounted as a chip (four pins, no casing)

Any ideas where I could learn how to build a simple circuit like this, I'd like one that lights up when activated by noise instead of beeping.

Thanks in advance,
Peter

 

Go to Electronics Goldmine @

http://www.goldmine-elec.com

and look up item# T7031. This is simple, striaghtforward and may serve your purpose.

 

[pcawdron]

Thanks for the lead... unfortunately, a search on T7031 at that site comes up blank. I've also searched on 'audio activated' but nothing came up - how did you find it? I'll have a good look through the site tonight when I get home.

Thanks,
Peter