Automatically switching light on and off in room - using evaluating unit responding to output signals of passive IR movement sensor and ambient light sensor

摘要

The output signal of the movement sensor (2), used to detect the presence of a person in the room, is collected via two switching threshold units (4,5) of differing values. If a person entering or leaving the room is detected by the greater value being exceeded, the light source (10,11) is immediately switched on if the ambient light is too low or switched off after a delay. The presence of a person who has already arrived is detected by the lower switch threshold. The evaluating unit (1) and threshold setters (4,5) can be realised by a microprocessor. The output signal of the passive IR sensor (2) can be fed to the evaluating unit via another input dependent on the threshold value, to register the noise level of the sensor. A further input (12) detects the manual switching of the lights. ADVANTAGE - Can detect large and small movements of people for energy saving without decrease in comfort.