Abstract: An electrically non-conductive separator having a hole formed therethrough is interposed between a pair of switch contacts having a modulus of elasticity. A cover of electrically non-conductive flexible material covers the switch contacts. Electrically conductive leads are electrically connected to, and extend from, the switch contacts. The positions of the switch contacts relative to each other are determined by differences in pressure and control the operation of an electrical circuit electrically connected to the leads to operate a circuit to perform a function.

Abstract: Electrically conductive leads of a radio alarm system electrically connect a relay, a source of electrical energy and a radio transmitter in a back up circuit. The relay is energized by electrical conductors of an electric circuit of the radio alarm system having switches, and maintains the relay normally open as long as the radio alarm system is in operative condition. When an electrical conductor of the radio alarm system is open-circuited, the relay is deenergized and closes the back up circuit to actuate the transmitter to transmit radio signals indicating that an electrical conductor of a closed circuit of the radio alarm system has been open-circuited.