Touch Switch

A touch switch is a switch that is turned on and off by touching a wire contact, instead of flicking a lever like a regular switch. Touch switches have no mechanical parts to wear out, so they last a lot longer than regular switches. Touch switches can be used in places where regular switches would not last, such as wet or very dusty areas.

Schematic

Parts

Part Total Qty. Description Substitutions C1 1 10uF 16V Electrolytic Capacitor R1, R2 2 100K 1/4 Watt Resistor R3 1 10 Meg 1/4 Watt Resistor U1 1 4011 CMOS NAND Gate IC MISC 1 Board, Wire, Socket For U1

Notes

1. The contacts an be made with just two loops of wire close together, or two squares etched close together on a PC board.
2. When activated, the output of the circuit goes high for about one second. This pulse can be used to drive a relay, transistor, other logic, etc.
3. You can vary the length of the output pulse by using a smaller or larger capacitor for C1.