Infrared motion detector

The GLMDA is designed to detect the motion of a human or animal both in daylight and at night and to provide a normally open relay output that can be used to activate many types of loads. The GLMDA also has terminals for connecting an optional photocell to prevent activation of the load during daylight.
Infrared motion detector - schematic

The GLMDA is 1.7 X 2.4 inches with circuit components on one side and a pyroelectric infrared sensor on the other side. The module should be mounted with the 2.4 inch dimension vertical for maximum sensitivity to horizontal motion. Four holes on the corners accept # 4 mounting screws. A Fresnel lens or other focusing device can be placed in front of the sensor to increase sensing distance by focusing infrared radiation onto the sensor elements. Sensitivity The component side of the GLMDA has a sensitivity adjustment R10 that controls amplifier gain and therefore range (detection distance). Turning the adjustment clockwise increases sensitivity and gives a greater range. The pyroelectric infrared sensor in the GLMDA will detect a human or animal more easily at lower ambient temperatures when there is a greater difference between the human or animal body temperature and surrounding objects. Day / Night control An optional external resistive photo-conductive cell (not supplied) may be connected to the terminals marked C to de-activate the circuit during daylight so that a load will be activated only at night. This is useful if the GLMDA is used to turn a light ON. Delay between sensing A single shot circuit controls the amount of time that elapses between motion events that activate a load. This is useful for applications where continued motion might occur and rapid repeat activation of...

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