How They Work
Motion detectors are electronic sensors that react to the infrared waves created by moving objects. The warmer the object is that moves across their field of “vision,” the more sensitive they are to it. When electronically connected to a light, the signal the detector picks up when an object crosses its path will trip the light, turning it on. Usually, the light also has a timer, which can be set for anywhere from one to twenty minutes. When no movement is detected for however long the timer is set, the light again goes off.
Common Uses
Motion detector lighting is commonly used as a passive type of security, designed to frighten would-be intruders away. For people who work odd hours, having to either leave or return home in darkness, decorative lights can be hooked up to a motion detector so that outside lighting comes on automatically as you leave or return home. These need not be extremely bright. Remote motion detectors can even be used as a type of silent alarm. If you put a detector in an outside area you want to protect from intruders without tipping them off, you can wire it to an interior light that will come on if anyone trips it.
Brightness
Most motion detectors are used for security purposes, to scare off intruders, and so are connected to very bright floodlights. Floodlights generally range anywhere from 150 to 300 watts when connected to a motion detector. You can, however, get soft lights in walkways or decorative carriage lights connected to a motion sensor. If you want to repel intruders, brighter is better. If you just want to light up your way as you come and go, softer lights can be a great convenience.
Sensitivity
Some motion detectors can cover a full 360 degrees. Most will cover a circular pattern of 240 degrees and can be set to pick up motion up to 70 feet away from their field of vision. Some cheaper motion detectors have a preset range. If you start getting false positives such as the light being set off by blowing leaves or a passing bird, it can be annoying. If you buy a detector with an adjustable range and adjustable aim, you can correct this problem easily while still enjoying the security that motion detector lights offer.