Patent ID: 7619206

Claim:
A switch comprising: a radiation emitter, an auxiliary radiation emitter, a controller configured to generate a periodic control pulse (Pc) at a first time interval to cause the radiation emitter to emit radiation for a duration of time and to generate a periodic test pulse (Pt) at a second time interval different than the first time interval to cause the auxiliary radiation emitter to emit radiation for a duration of time, a radiation receiver, and a cover positioned over the radiation emitter, auxiliary radiation emitter and radiation receiver, the radiation receiver adapted to receive at least part of the radiation emitted by the radiation emitter and at least part of the radiation emitted by the auxiliary radiation emitter, the radiation receiver configured to generate one or more reception signals whose values depend on the radiation received, the controller configured to receive and evaluate the one or more reception signals to determine if the cover has been pressed by a user and/or to determine if a malfunction exists in the switch.