(On the right side)Can be uses as a button switch or by replacing the 1M resistor and the button with 2 touch plates near to each other it becomes a touch switch because your finger will become the new 1M resistor.
(On the left side) by replacing the button with a small circuit that detects hand claps (with electret microphone)you will get a hand clap detector switch. Every 2 claps the switch will change state.
