A common misconception is to confuse them with motion sensors. A motion sensor uses IR beams to detect movement. This makes it great at detecting passage over a general area, but it also makes it less precise and somewhat more expensive. A door sensor, on the other hand, just uses magnets. It can be used to detect the opening and closing of any hinged mechanism, be it a door, window, or something similar. It doesnt have to be a hinge. Any component that twists or turns in its operation — say, a...
