Smoke alarm with timed evaluation of a backscattering signal, test method for functionality of a smoke alarm

摘要

The smoke alarm (100) has a light transmitter (111) attached to a mounting surface of a printed circuit board (105) and transmitting an illuminating light (111a). A light receiver (112) is attached to the mounting surface adjacent to the light transmitter, and receives a measurement light (112a), which results from back-scattering of the illumination light at a measurement object located in a detection space (115). A data processing device (135) is coupled to an output of the light receiver and evaluates temporal changes of an output signal provided by the light receiver. An independent claim is also included for a method for detecting a functional capability of a smoke alarm.