Micro Switch

A micro-switch works by detecting the movement of physical objects and indicating it to an electrical circuit. It is normally used to identify objects on conveyor belts, in security alarms, to tell elevators where to stop and to let microwaves know when the door is closed.
The micro switch works by using very physical force through the use of a tipping-point mechanism. The switching happens reliably at specific and repeatable positions of the actuator, which is not necessarily true of other mechanisms. Internally, it has a flat metal spring that must be bent to activate the switch. Inside is a small curved spring.