The
ISD1000A is a
specialized microcircuit in a 28-pin
DIP design. It is almost a complete
voice-
recording system. Add in a
microphone,
speaker, a couple of
resistors and
capacitors and you have a
discreet recording and
playback device. It handles 20 seconds of audio, and makes a great little
practical joke.
You can pick them up at places like Digi-Key or Radio Shack for about $15.