Heat Detection Sensors - Some motion detection technology utilizes sensors to detect heat differences. This type of motion sensor would be best utilized for an indoor motion detector light instead of an outdoor one. Signal Blockage Sensors - Another type of motion detection technology detects blocked signals. Whenever something crosses in front of the sensor, it physically blocks the signal that the sensor is emitting, letting the lights know that there is movement and that it is time for them to turn on. This type of sensor is great for both indoor and outdoor motion detector lights. Light Change Sensors - Light change detectors track ambient light and turn on your lights whenever they detect a big enough change in lighting. This type of motion detector light is usually used outdoors and is most often set to activate only when it is dark outside, like a front porch light. Contact Sensors - Based off of their name alone, it is pretty easy to figure out how contact sensors work. Usually placed on doors or windows, contact sensors activate when the direct signal from one part of the sensor to the other is interrupted. This happens when the door or window they are fastened to is opened.