This is a neat and useful sound / voice recording module. It has built-in microphone and can record up to 10 seconds of sound / voice message. There are three ways to play back:
The module has three buttons: Record, Trigger-Playback (PlayE), Walkie-talkie-Playback (PlayL), two slide switches:Loop, Feed-through (which passes the microphone signal directly to output, like a voice amplifier), speaker connector, and microcontroller pin headers (VCC, GND, RECORD, PLAYL, PLAYE).
The package includes: one sound / voice recording module.
Optional add-on (not included by default): mini-speaker, AASaver (can be used as power source, providing 3.3V or 5V selectable output)
Additional technical details can be found at: http://www.elecfreaks.com/wiki/index.php?title=Voice_Record_Module_-_ISD1820