How to Test a Motion Detector

Install your motion detector and any associated electronic hardware according to the instructions supplied with the device. Aim the motion detector toward the area you wish to detect motion in. You may be able to adjust this by hand, or might be required to use a screwdriver to move it.

Flip the switch on your motion detector to TEST mode, if it has one. During TEST mode, your motion detector will detect motion as it does normally, but will switch off the associated electronic device -- such as spotlights -- more quickly than it would in normal usage. This makes it quicker to adjust the motion detector's settings and retest it in a new configuration.

Walk in front of your motion detector. It should activate whatever electronic device it is connected to, i.e., turn on a spotlight. If it does so, your device is installed and configured correctly. If not, you will need to adjust your motion detector to get it to work correctly.

Determine any faults with your motion detector configuration. If the motion detector fails to detect movement when you walk in front of it, for example, you should examine how and where you have installed the motion detector sensor. It should be installed 5 or 6 feet from the ground, facing downward. If it is installed too low, or facing upward, interference or glare from the sun can prevent the detector from identifying movement.

Check to see if your motion detector is detecting movement from a flag, swimming pool, air conditioner or other object if it activates without you walking in front of it. This will cause problems because your motion detector will not be able to discern between "background" movement, such as from a flag waving in the breeze, and "real" movement, such as somebody walking in front of the detector. If your motion detector is picking up ambient motion, you should adjust the direction of your motion detector so whatever is causing the movement no longer interferes with it. If this isn't possible, you can use black electrical tape to mask off the part of the motion detector that "detects" the ambient motion -- preventing it from activating unnecessarily.