Abstract: An optical attenuation measurement system is provided for obtaining signals proportional to movement of a system to which it is attached. The measurement system includes a light source positioned within a length of conduit in which the light emitted will produce multiple reflections. A fiber optic cable is slidably disposed within the conduit to transmit the radiation emitted from the light source gathered thereby. The relative displacement of the fiber optic cable to the light source produces a signal as a function of this displacement which is converted into electrical signals by a light detecting element at the opposite end of the cable. The system is particularly useful to form an interactive device for control of a remote intelligent machine, robot or the like. For example, the system may be used on an operator's hand to detect movement of the hand and fingers for controlling a robotic hand which will mimick the operator's hand movements.