Bests & Worsts Reviews from Amazon

The third night after installation we got two false alarms in the middle of the night. I know they were false because we have a camera taking snaps of any movement in the area the Guardline was supposed to be covering. The directions say there are two causes for false alarms: moisture in the unit or low batteries. The nights were cold but dry and the batteries were new. I used the rain cover that came with the device. A second problem was the unit sometimes would not pick up motion until a person was six feet away; other times it alerted to someone 12 feet away and several times when 35 feet from the sensor. In other words, picking up movement was a random event. At all times, the distance detection was set for 40 feet. The instructions (p. 15) say to remove the window covering over the lens to widen the angle of detection. I tried this but it didn't help. I think this might work better for a driveway with a short detection distance and a large vehicle to trigger it. One hint: Although the instructions only refer to using AA or AAA batteries, if you live in a cold climate and decide to try this device, I suggest you do as the last agent told me and use lithium batteries. Update to my review after reading the Customer Support response. I did install the sensor as specified in the directions at the very beginning. After a dozen or so further exchanges with Support, which were mostly non-responsive because they did not read what I said, I returned this product to Amazon. I found a better solution at half the price with a more intelligent design, primarily because you don't have to unscrew four screws holding the mounting plate in order to remove the batteries and change the settings. So far, the Bibene DW9 Smart Driveway Alarm seems to be functioning as designed with no false alarms.