This voice recording and playback circuit is designed using ISD1012, ISD1016 and ISD1020 integrated circuits that allow recording and playback of certain sounds, for a period of several seconds.
These voice recording and playback circuit contain a nonvolatile memory integrated that can store recorded sound without requiring any power supply for a period of not less than ten years.
The last two digits of IC indicates the length of the message which can be recorded and played in seconds.
The circuit also contains a microphone amplifier and output amplifier.
Switch S2, in the open position, switch circuit in "power down". Most of the circuit is then disconnected, which reduces power consumption.
Triggering sound recording or playback is done by closing S3 (which should remain closed during recording).
If you want one for recording, playback higher can use ISD25xxx type circuit allows recording up to 120 seconds.