False alarm prevention device for infrared movement detector - has processor which generates alarm control signal only with occurrence of signal from external light sensor, when path of electrical signals from infrared detector deviates from preset course

摘要

The false alarm prevention device has a processor (4) with a light sensor (5) for detecting foreign light. The processor only generates a control signal (s) when the electrical signals of the infrared detector (1) changes from a predetermined pattern. The change corresponds to the change in the foreign light. The processor stores the predetermined pattern of the infrared detector electrical signals. The electrical signal of the infrared detector is converted into a digital signal using an A-D converter (3). The converter operates using successive approximation. The processor is a microcontroller (9), and is connected to a bus system with bus protocol control. ADVANTAGE - Uses simplest possible circuitry, without optical filter and corresponding mechanical components. Can be used with any infrared detector.