Title: Interresting idea, handy in some situations
Review: I purchased this to let me know when someone was coming at work. The environment is very hot, and can give the occasional false positive depending on where it is placed. The hotter the environment, the more false alarms you'll get (probably mid-high 90s and above). Nice to have portability and 2 volume settings. Works pretty well, but is not a replacement for a security system. More a convenience. Haven't used it more than a day, but so far it works as expected.Also, this is a passive infrared sensor. It will not work through glass. It checks for rapid changes in heat emitted by objects crossing it's path. It does not emit any light/signal for detection (based on what I have read online about the function of passive infrared sensors).
Is this product review negative?