Non-contact key

摘要

A non-contact switch movs from an off position to an on position when a lossy material enters a sensitive area of the switch. The non-contact switch comprises a transmitting element and a sensing element. The transmitting element is capable of radiating a signal. A portion of the signal passes through the sensitive area of the switch. The sensing element is capable of receiving the signal. When the received signal is less than a predetermined level, the received signal represents the lossy material entering the sensitive area of the switch.