Keyboard with thumb operated spacebar curser controller

A keyboard with a thumb-controlled curser. In a preferred embodiment a circular aperture about one centimeter in diameter is provided in the spacebar of the keyboard. A keyboard user controls the position of the computer curser by moving a portion of his thumb across the port. A light source illuminates an exposed surface of the user's thumb as it moves across the port. Light patterns reflected from the user's thumb are focused on a sensor. The output from the sensor is transmitted to the computer processor where the thumb movements monitored by the sensor are turned into control signals for controlling the position of the curser on a computer monitor.