Abstract: An apparatus detects the presence and location of at least one object in a field. The apparatus comprises a rotating arm which spins around the field, a position sensor for detecting the angular displacement of the rotating arm relative to a fixed point, and a processor. The rotating arm includes a transmitter and an opposing receiver array mounted thereon and fixed relative to each other. The receiver array includes a plurality of receivers located horizontally coplanar with each other. The receivers are concentrated towards one side of the receiver array which is aligned with a center region of the dartboard. The transmitter outputs a detection beam that emanates from a single point, such as a divergent beam. The detection beam overlaps the field and is simultaneously received at all times by the plurality of receivers of the receiver array. The receivers detect changes which occur in the field as a result of an object being in the field, manifested by shadows on the field.

Abstract: An apparatus for detecting the presence of at least one object in a field having at least one through-beam detection device with at least one transmitter and at least one opposing detector to create a detection beam that overlaps the field.

Abstract: An optical system and method for detecting the presence and location of at least one stationary or moving object in a field. The optical system has at least one light source to generate a beam, which beam is scanned by at least one first reflecting surface to generate a plurality of beams. The beams are overlapped across the field by at least one second reflecting surface and their intensity is measured by at least one detection means.