Motion sensor which produces an asymmetrical signal in response to

Abstract

In one embodiment of the invention, a plurality of sensors are placed over the joints of a hand. Each motion sensor comprises an optical fiber disposed between a light source and a light sensor. An upper portion of the fiber is treated so that transmission loss of light being communicated through the optical fiber is increased only when the fiber bends in one direction. In another embodiment of the invention, a flexible tube is disposed in close proximity to a finger joint and bends in response to bending of the finger. A light source and light sensor are provided on opposite ends of the tube for continuously indicating the extent of bending of the tube. A wedge is disposed between the tube and the finger for setting the tube straight when the finger is hyperextended for eliminating the symmetry of the output signal which ordinarily would result from bending of the tube on opposite sides of the axis of movement. In a further embodiment of the invention, a light source and light sensor are positioned in close proximity to a finger joint so that bending of the finger toward the palm causes the source and sensor to move away from each other. Bending the finger in the opposite direction causes the source and sensor to move toward each other.