A clap switch circuit is a classic beginner’s project. Equipment can
be switched on and off by just clapping your hands. Add a tiny microcontroller and you can easily build-in some more useful features.
The microcontroller in this circuit makes it a simple job to add some useful
features that are not seen on other clap switch designs:
– Changeover relay contacts enable the unit to be wired in conjunction
with a manual changeover switch so that manual override of the switched
equipment is always possible.
– The unit is only responsive to a specific sequence of sounds i.e., two
claps within a defined time window.
– A safety feature masks the input for a given time window if misuse
(repeated commands) is detected (useful if children have discovered how it works).