Actuation device with at least one optoelectronic sensing element, esp. contact sensitive reflection light barrier,

摘要

The device has a comparator (K) for detecting the operation of a key by comparing an alternating light signal, esp. a pulsed alternating switching signal, reflected from a reflection body with a threshold value dependent on the degree of reflection of a d.c. test light signal transmitted towards and reflected from the reflection body (RE). Where several sensing elements are used, each has an associated transmitter (S) and receiver (E). Each can have a contact sensitive infrared reflection light barrier arrangement for a cooking point. The sensing elements are successively, esp. cyclically, connected to the comparator.