Abstract: A sensor device that provides a relatively uniform electric field between a diaphragm and a substrate, regardless of the displacement of the diaphragm is disclosed. The sensor device provides a uniform spacing between the diaphragm and the substrate over a selected range of diaphragm displacements. A double layer diaphragm is disclosed that includes an upper support member and a lower electrode plate. The lower electrode plate is attached to the upper support member by a post member, and the post member is only attached to the center region of the support member. In another embodiment, an electro-mechanically controlled switch sensor is provided that uses an electrostatic force between the diaphragm and the substrate to produce a bi-stable snapping action.