A very simple electronic touch switch circuit can be constructed using this schematic diagram . This electronic touch switch circuit is based on two transistors an can activate a relay , when the touch sensor is pressed .

The touch sensor can be constructed using a small piece of a printed circuit board ( two small tracks with a 2 mm distance between each other ) . This circuit is powered using a 12 volts DC power supply , so the relay used for this project must be a 12 volts relay . This circuit is working very simple , when both plates of the sensor are touched the skin resistance will activate the circuit .