Abstract: An apparatus useful for detecting the speed and/or position of an object moving along a defined path and more particularly to such an apparatus configured to minimize the spacing between a sensing face of the apparatus and a target surface on the object. Embodiments of the invention are particularly suited for sensing the speed of a rotating member, e.g., a gear, by utilizing a sensor, such as a Hall-effect sensor, to detect the movement of each gear tooth past the sensor. An apparatus in accordance with the invention is configured to mount the sensor for adjustable positioning along a sensor path between an initial position and a final operational position. Movement of the sensor along the sensor path is restricted, e.g., by frictional engagement, but can be overcome by contact with the target surface so as to move the sensor to its final position with the spacing, i.e., airgap between the sensing face and the target surface, minimized.