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.