A highly compact PIR sensor housed in a TO5 package fitted with a zoned fresnel lens. The sensor detects infra-red radiation in the low infrared spectrum (10µm wavelength) which is emitted by human movement.
The sensors are able to detect a change in temperature from object to ambient from as little as 3°C. Changes in the level of detected emission are evaluated by a window comparator and if the change exceeds the upper or lower threshold the output level of the sensor goes high and can be used to trigger external circuitry.
