Review on The Thing System by Jeremy Byard

I like that it's easy to use, has many different sensors, is cheap (and even free), has an app for both Android and iOS, and works with other devices in my house. It doesn't have any kind of built-in display or light so if something breaks down there isn't much recourse unless you're willing to pay more money. We've had it set up as our alarm system since we moved into this home about two years ago. When someone comes over, they press their phone against the sensor which sends us alerts via text message or email when anyone enters the room. This allows us to know who's coming without having to look at a device.