Cerberus Ag

Walter Meier

Kurt A Muller

Alfred Wuthrich

Kurt Mueller

A space surveillance apparatus includes at least one source of sonic radiation driven by a driver circuit as well as a processing or evaluation circuit. Upon movement of an object, or presence of a foreign object within a monitored space, the processing circuit triggers an alarm signal. Each sonic source defines the volume of its own monitored space, according to the equation:

Space surveillance apparatus with sound source and method of short-range

An intrusion detector evaluates the infrared radiation emitted by an intruder within a closely defined zone or area by means of a virtual protective curtain. Uniform sensitivity independent of incident angle of the radiation is provided by a cylindrical Fresnel lens of small thickness, which divides the field of reception into sharply defined strips or elongate zones of substantially uniform sensitivity. The longitudinal axis of this Fresnel lens defines an arcuate sector of a circle whose radius is determined by the focal length in perpendicular direction, and an infrared sensor is arranged at the circular center point, i.e., the focal point of the curved Fresnel lens. One particularly advantageous embodiment of the intrusion detector includes a double sensor configuration, equipped with several sensor elements cooperating with one or more cylindrical Fresnel lenses, thus covering a number of separate zones for simultaneous radiation detection.

Infrared intrusion detector

In an infrared intrusion detector which evaluates the body radiation of an intruder by means of a dual radiation sensor having two sensor elements arranged in a differential circuit for emitting an alarm signal, a functional supervision and detection of an attempt at sabotage, e.g., by covering or spraying the entrance window, are achieved by asymmetric irradiation of the two sensor elements through the entrance window by a radiation source. The asymmetry can be achieved by disposing the radiation source outside the plane of symmetry of the sensor elements or by an asymmetrically disposed auxiliary reflector.

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Mannedorf, Switzerland

Walter Meier