The ceiling-built-in motion sensor / presence detector KINASGARD® DBWF detects the presence of persons and motions and has a switching contact output. The motion detector is used for the observation and recognition of conditions and for the motion-dependent control of room functions, e.g. for lowering temperatures in unused rooms. The ceiling motion detector is installed in suspended ceilings in corridors, offices, apartment rooms and business facilities. The measuring transducer is accommodated in a separate enclosure apart from the sensor.