Motion is measured by detecting the disturbance of Wi-Fi signal reaching Motion Wi-Fi Sensing Plugs as someone goes through the field created by all the devices that create the Motion Zone. When the minimum threshold of disturbance that qualifies as motion is detected, the Zone reports that motion has started and it will continue to monitor the motion until the disturbance no longer reaches the minimum threshold for 30 seconds. At this point, the Motion Zone will report that the motion has stopped.