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:

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:

The contacts an be made with just two loops of wire close together, or two squares etched close together on a PC board.
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.
You can vary the length of the output pulse by using a smaller or larger capacitor for C1.