A rotatable device has a stationary base including bottom and top surfaces. The bottom surface has a first set of coupling electrodes configured to receive a reference signal from first electrodes of an attached input device, and second and third sets of coupling electrodes each configured to receive resulting signals from a second set of input device electrodes. The top surface of the stationary base has first, second and third top regions respectively connected to the first, second and third sets of coupling electrodes. The rotatable device further includes a rotary wheel, configured to rotate relative to the stationary base, with a bottom portion provided with alternating conductive and non-conductive regions and configured to align with the top portion of the stationary base. The resulting signals of the input device are modified by the relative positions of the stationary base and the rotary wheel.