I lost faith in things that are noise activated after I bought a key finder. Supposedly you whistle and it beeps to let you know where your keys are. It never worked when I would whistle, but every time a train came by the house it would go off
Either the sensitivity was set too high - so the door opening and closing would do it... Or it was too low and you had to be right next to it for it to work.
Both of which kind of ruined it for me/us in our apartment. Unfortunate, too.
We had one when the kids were small. It really did work. Once the Kids figured it out and would make a game out of it, and the dog would get frustrated barking because he could not, we just unplugged it.
Used one last several years on the Christmas tree. The plug was kind of hard to reach and outlet was not on a wall switch. It worked well and plan on using it again this Holiday Season.