SENSING APPARATUS AND METHOD

摘要

There is described an apparatus which monitors the orientation of or the rotational movement of a substantially spherical body. The apparatus comprises a substantially spherical body with at least one resonant circuit fixed thereto. A transmit aerial generates an alternating magnetic field in the region of space including the spherical body which induces an electric signal in the or each resonant circuit, and a receive aerial receives an induced sense signal generated in response to said induced electric signal in the or each resonant circuit. The electromagnetic coupling between the transmit aerial and the receive aerial via the or each resonant circuit varies in accordance with the orientation of the spherical body so that the induced sense signal in the receive aerial varies in accordance with the orientation of the spherical body.