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Adjust Motion Detectors

Learn the fine art of motion detector sensor adjustment and stop wasting energy illuminating passing cars and wandering neighborhood cats. With these tricks and a little trial-and-error, you can turn that hair-trigger nuisance light into a useful security feature.

By the DIY experts of The Family Handyman Magazine

Tame a hyperactive motion detector

An outdoor motion detector light can save electricity and scare off intruders. But if passing cars or the neighbor's dog constantly triggers the light, you don't get either benefit. To stop unwanted “trips,” you have to limit the “detection zone,” the area where the sensor can see moving objects.

First, aim the detector. Turn the sensor head right or left and up or down so that its field of vision is roughly centered on the area you want to cover. To make the head stay put, you may have to tighten screws or ring nuts (Photo 2) on the arm that supports the head. Next, set the “on-time” switch to “test” (Photo 1). This will let you determine the detection zone by walking across the detector's field of vision. When it sees you, the light will go on for a couple of seconds. (Your detector may need a one- or two-minute warm-up period before it starts to work.)

If the detection zone in front of the detector is too long, aim the head down slightly. If the zone is too short, raise the head, but keep it at least 1 in. from lightbulbs and lamp covers. When the range is about right, make finer adjustments using the range dial (Photo 1). It may be labeled “range” or “sensitivity.” Start with the dial set at the maximum range and turn it down to shorten the zone.

If the zone is still too wide, narrow the lens opening with electrical tape (Photo 2). This is a trial-and-error process that can take a few minutes. Normally, you need to apply narrow blinders only to the right or left ends of the lens, but you can cover as much of the lens as you like. When the length and width of the zone are just right, reset the on-time switch.

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Adjust Motion Detectors

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