Rotational direction detecting

A sensor for sensing a direction of rotation of a body. The sensor comprises a first accelerometer arranged, in use, on the body, and having a first sensing direction; and a second accelerometer arranged, in use, on the body and having a second sensing direction. The two accelerometers are arranged such that the first and second sensing directions are not parallel to one another and are not parallel to the axis of rotation of the body, such that there is a phase difference due to gravitational effects between the outputs of the accelerometers when the body rotates in use. Means receives the acceleration indicative output signals from the first and second accelerometers and determines the phase relationship between the two signals to thereby determine the direction of rotation of the body.