Lighting Motion Detectors
Reliable motion detectors are a crucial part of any home security system. Suddenly flooding an area with light can provide an excellent first line of defense to deter intruders. These same motion sensors can also provide you, your family, and guests with an added degree of safety. Whether you're taking out the garbage, navigating your way along the side yard, or simply walking around outside, motion detectors can turn on lights when you need them without the cost or light pollution of leaving them on when you don't.
A basic all-purpose motion detector can provide 110 degrees of coverage-50 feet out and 70 feet wide. This is useful for monitoring large swaths of the front or back yard.
For longer, narrower strips, such as a side yard, a 180 or even 200 degree motion sensor makes more sense. It can cover along the walls of the house to a width of 100 feet and 30 feet out. A "double look down" lens will provide an added degree of security for any sensor, monitoring closer areas that might be missed by other detectors. It's even possible to get a sensor with 360 degrees of sensitivity. This is more than you need for a wall, but it works well when attached to a post in the middle of the yard. Or you can use up 270 of those 360 degrees by positioning it at the corner of your house.
You want the detector to have an easily adjustable sensitivity as well. It will take a little experimentation to make sure it's triggered by events that you care about but isn't fazed by the dog next door.
A good motion detector should have a tough, vandal-proof lens and grill to prevent it from deliberate attacks. It should be corrosion proof and weatherproof to protect it from the climate.
Most motion detectors have a basic spotlight design that attaches to an overhang or to the wall of your house and can be angled from there. Others look like half domes or small plates and attach unobtrusively to the wall. These can be used where the line of sight is clear in all directions directly from the wall. If there are bushes along the wall, you may want something that sticks out a little farther to look around them.
It helps to have a motion sensor that comes with a timer or a darkness detector so it can be set to trigger only at night. A motion sensor that emits sound (such as a siren or loud beeping) may be overkill in most situations but can provide an additional level of security that may be worthwhile.
Make sure that whatever motion sensor you purchase is rated to control the number of watts you plan to attach to it. This shouldn't be a problem. Many of them have a 1000 watt switching capacity. And even the lower powered ones can handle 500 watts incandescent or 250 watts fluorescent.