The Motion Sensor is looking for a warm object moving across its field of view. If it detects movement and heat it will trigger an alarm. Some common triggers include things such as heating vents, space heaters, pets that are over 40 pounds or able to climb up onto a piece of furniture near the Motion Sensor. If there is anything in the environment that the Motion Sensor can see that you believe may be causing the alarms, move the Motion Sensor to a new location to avoid these possible triggers. If you believe your Motion sensors alarm was a false alarm, please contact Customer Support for troubleshooting assistance.