An optical transducer (200) comprises a light source (230) for emitting radiant energy, and an elongate light collector (204) positioned for receiving radiant energy from the light source (230). Radiant energy projected by the light source (230) is received on the light collector (204) and is transmitted along a length of the light collector (204). A portion of the transmitted radiant energy exits the light collector (204) along its length through a gap (205) to thereby vary the intensity of light along the light collector length. At least one photosensor (232) is positioned for detecting the intensity of radiant energy incident at a particular location on the light collector (204). In this manner, the intensity of radiant energy detected by the at least one photosensor (232) is indicative of at least relative position between the incident radiant energy and the at least one photosensor (232).