Siemens Building Technologies Ag

Siemens Building Technologies, Ag Cerberus Division

Intermec IP Corporation

Bruker Switzerland Ag

Stefan Hegnauer

Roland Küng

Hansj&uuml;rg Mahler

Michael Schenkel

A motion detector based on the Doppler principle contains a microwave module for emitting a microwave signal containing at least two frequencies into a room under surveillance and for receiving the radiation reflected from the latter. An evaluation stage is connected to the microwave module and generates first and second Doppler signals from the received radiation. The first and second Doppler signals have a phase difference which is proportional to the distance of an object reflecting the microwave signal. The phase difference is determined by an integral transformation. In addition, the relative size of an object and the direction of travel of an object reflecting the microwave signal can be determined by the evaluation stage.

Motion detector based on the doppler principle

The infrared detector contains an entrance window for infrared radiation, an infrared sensor with an evaluation circuit and an anti-masking device having an optical transmitter and an optical receiver for detecting phenomena or optical changes immediately in front of the detector and/or changes in the optical properties of the entrance window. The signals of the anti-masking device are evaluated in two channels, wherein one channel responds to temporally limited phenomena or changes and the other channel responds to temporally stable phenomena or changes. A combined evaluation of the signals in the two channels takes place. In the combined evaluation, the channel processing the signals of the infrared sensor is preferably also included. As a result, the infrared detector acquires an increased immunity to false alarms and a higher sensitivity.

Passive infrared detector

Growing community of inventors

Dübendorf, Switzerland

Stefan Hegnauer