Motion detectors are widely known for their role in home security systems, but their usefulness extends far beyond guarding ...

The presented schematic shows how to build a simple PIR motion sensor. PIR sensors allow motion sensing, it is almost always used to detect whether someone has moved in or out of the sensors range.

Movement-based lighting suggests activity inside, which helps deter opportunists. Automatic light on stairs, landings and entrances reduces falls and avoids leaving circuits on. Hands-free access ...