Abstract: Apparatus for controlling a gaming device including a plurality of rotatable reels provided with indicia has an input circuit associated with the reels for detecting reel positions at every instant in time. A computing circuit is connected to the input circuit for receiving reel position signals and maintaining data on reel positions. Connected to the computing circuit is a comparative, or win, circuit arranged for receiving reel position signals from the computing circuit and for comparing indicia on each of the reels as a function of the position of the reels for determining if a predetermined match exists. A pay circuit connected to the comparative circuit is actuated by a match detected in the comparative circuit to effect a pay-out by a hopper assembly of the associated gaming device. Included in the input circuit is an optical sensing assembly arranged for cooperating with gaps and openings provided on the reels for determining positions of the reels.