This is a very simple touch sensor switch that is build with the 555 timer IC. You just need to touch the metal plate and the relay gets energised and is kept in this state for about 100 seconds, then ...

Schematic of IR Beam Breaker Circuit TSOP1738 IR sensor module responds to only 38 kHz pulsed infrared rays. It will not sense continuous IR ray from the IR LED. So a transmitter circuit (as one in TV ...