A rotary position sensor is includes a static portion that comprises a first board and a second board and a rotatable portion that comprises a third board. The second board comprises a first planar coil; and the third board comprises a second planar coil as well as means for generating luminance. The first board comprises means for receiving the generated luminance and the first planar coil of the second board is configured to transmit power to said second planar coil of said third board via inductance. The power received by said second planar coil is configured to supply a current to said means for generating luminance; and said means for generating luminance is configured to emit a luminance signal which has a luminance level.