A sensor having a shutter mounted to a segment of a molded hinge for movement within a housing in opposition to a light path between an LED and photodetector is described. The molded arm includes a hinge and the segment of the molded hinge extends outside the housing connected to the elongated arm. One end of the elongated arm engages a moving photosensitive surface and deviations of the edge position of the photosensitive surface rotate the shutter in relation to the light path between the LED and photodetector for tracking the edge position of the moving photosensitive surface by providing signals representing shutter position.