Abstract: A washing machine includes a cabinet, a splash tub located within the cabinet, and a support system resiliently supporting the splash tub relative to the cabinet. A spin tub is located within the splash tub and a drive system spins the spin tub about an axis of rotation during a spin cycle. A sensor detects an out-of-balance condition during the spin cycle characterized by oscillations of the splash tub. The sensor includes a target attached to the cabinet having a reflecting surface, a light source attached to the splash tub and positioned to direct infra red light toward the reflecting surface, and a light receiver attached to the splash tub and positioned to receive infra red light reflected from the reflecting surface. The reflecting surface has a pattern of varying reflectivity so that the light receiver receives a different quantity of infra red light when the splash tub moves relative to the cabinet.