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.
Click here to download the full size of the above Circuit.
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.
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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