I bought one of these to give me a heads up when someone comes up my outside stairs. I set it up this morning and it worked well until this afternoon when it got windy out. Even though I positioned it so it did not see trees or other items that move in the wind, it was beeping constantly. It only stopped when the breeze stopped. If this unit had some way to reduce sensitivity it might be more useful, but as it is I can't recommend it for outside use. It might work indoors, though it false triggers even when placed inside facing out a closed window. I also tried reducing sensitivity by adding thick tape in front of the sensor. It still false triggered constantly. I'll keep working on this to see if there is a solution.