How Do Outdoor Motion Lights Work?

Here is a sideview of a motion light's range of motion. Illustration by Adam Crowson

An outdoor motion light has a sensor attached to it that is meant to light up when something moves within the sensor's range. The sensor is what makes an outdoor motion light work as it is used to detect movement inside a set coverage area and force the light to light up.

If the motion light is mounted to the side of the house, then the sensors typically have a coverage area of a half-circle with a radius of approximately 50 feet. Once movement is detected inside this area, the sensor triggers the light to automatically turn on and illuminate the area for a set amount of time.

Outdoor motion lights also have settings that allows users to keep the light on all day, only function by the flip of the switch or light up during daylight -- in addition to the sensor settings.