Abstract: A hinge position sensor comprises first and second members connected together to provide a hinge, and an optical fibre or wave-guide connected between the first and second members to provide a communication link between the first and second members. A laser or LED is coupled to the optical fibre or wave-guide to transmit optical signals between the first and second members and the optical signal is received by a photo-detector. The optical fibre or wave-guide is physically distorted by actuation of the hinge such that light escapes from the optical fibre or wave-guide. The optical power level received by the photo-detector is used to determine the position of the hinge.