Abstract: A rotary switch includes a keylock housing having a collar disposed therein and a rotor disposed in a switch case housing to provide an internal labyrinth geometry. The collar includes a plurality of spaced mechanical stops to provide multiple mechanical travel options determined by the orientation with which the collar is disposed in the housing. Thus the stop collar may be disposed in the keylock housing in a plurality of different orientations with each of the orientations providing a keylock mechanism disposed in the keylock housing with a corresponding mechanical travel. The internal labyrinth geometry provided by the rotor-switch case housing assembly increases the electrical path length through which an electric charge must travel. Thus, the rotor-switch case housing assembly provides the rotary switch with protection from electrostatic discharge.

Abstract: A motion sensor for use within an implantable medical device provides a digital output signal that can be connected directly to the digital processing and control circuits of a pacemaker or other device. This signal may be used to adjust the basic pacing rate of the pacemaker as a function of the physical motion or activity that is sensed. The motion sensor includes an enclosed housing having conductive element therein that partially fills the space of a cavity within the enclosed housing. The conductive element is free to roll, flow or otherwise move around the inside of the housing in response to external forces. The external forces that cause the conductive element to move include the physical motion of the patient as well as the force of gravity. As the conductive element moves within the enclosed housing, it makes electrical contact with at least two of three electrodes that are selectively spaced around the inside periphery of the housing.