ABSTRACT
Specialised position sensors, such as linear inductive position sensors (LIPS) are obtainable, but are very expensive. They also need complex circuits to process the signals they produce. However, cheaper devices often can be used instead. For example, a microswitch (p. 105) can be used to detect whether an object is in position or not. It can tell us whether a cupboard door is open or closed. Better, use two microswitches, one for ‘door open’, and another for ‘door closed’. When the door is halfway open neither switch is closed.
