US Patent 10006785 Displacement sensor

A displacement sensor includes a resistive element and a wiper element. The wiper element is separated from the resistive element in a parked mode the wiper element is in sliding electrical contact with the resistive element in a sensing mode. A user input interface may be coupled to at least one of the resistive element and the wiper element, wherein whether the displacement sensor is in the parked mode or the sensing mode is dependent on actuation of the user input interface.