PIR (passive infra red) sensors are can be used for security and practical applications around the home. One of the most common places you will find them is used in conjuction with an LED flood light. Essentially a PIR is a switch that turns on for a period of time when it detects infra red through heat. So it will detect the body heat of an unwanted visitor and act as a deterent. It will also provide practical light and turn on when it detects you taking the rubbish out or returning from a night out.
We have fitted many PIR sensors to control: security lighting, hallway lighting, WC lighting, porch lights, patio heaters and garage lighting. They are particularly useful in rooms where kids tend to leave the lights on. There main advantage is they turn themselves off!!