Abstract: A door obstruction detector employs an optical device, such as a segmented Fresnel lens, and a PIR sensor attached to a moving door, so that the optical device causes an image of an object, in a detection zone, to move across a sensing region of the PIR sensor when the door moves. When the object is sensed in the detection zone, a drive signal is generated for controlling movement of the door. Thermistors can be used to compensate for variation in ambient temperature to adjust detection sensitivity.
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