the following specification discloses a directional optical encoder including a track ball . the track ball is supported within a case and moves against two respective shafts for providing positive and negative x and y movement . the shafts turn circular optical disc encoders wherein a beam of light passes through a slotted disc to be received against a sensing device , such as an optical sensor . the disc is a round disc having slots in order to provide rotationally pulsed outputs to a light sensor on the opposite side of the disc from a light source , such as a light emitting diode . on each shaft , a pendulous shutter is journalled with a fractional or clutched helical spring engagement for providing movement of the shutter in either the plus direction or the minus direction respectively for the x and y shafts . the shutters provide for shuttering of the light source to one of two light sensors to indicate minus or plus movement , depending upon which particular sensor is being covered . the attendant output from either the minus or plus sensor for each respective x and y shaft allows for a pulsed output directly to a circuit without further conditioning , modification , or decoding to determine direction .