Motion detectors are small electronic eyes that detect infrared waves—heat waves that radiate from moving objects. When the detector senses an object moving across its field of view—especially warmer objects such as people, animals and cars—it electronically turns on the lights. The motion sensing light stays on anywhere from 1 to 20 minutes, depending on how you preset the timer. Then the detector automatically shuts the light off unless it continues to sense movement. A photocell deactivates the motion sensing light during daylight hours. An outdoor motion sensor light will react to the movement of your dog, an approaching person, a passing car or sometimes even wind-blown leaves.
Where to install motion sensing lights
For best effectiveness, position a motion sensor light to cover the walks leading to your front and back doors and the driveway. That way the lights will come on when you come home at night. You can also use them to light up decks, patios and any potentially hazardous locations such as around stairways and swimming pools.
If improved security is a priority, position the motion sensored lights to cover all the approaches to your house, including fence gates, the patio door, the darker areas of your yard, and around trees and bushes. Good lighting can’t guarantee security, of course, but it’s one of the best low-cost ways to get unwanted intruders to back away.