COMPUTER INPUT DEVICE USING AN ORIENTATION SENSOR

A device for controlling a cursor on a data terminal display screen. The device is in the form of a headset and includes an orientation sensor which provides an electrical signal related to the orientation of the device without it being adjacent to any fixed surface. The orientation sensor includes a hollow spherical housing having at least one light source/detector pair mounted opposingly in the inner wall, along an axis extending through the center point of the housing. The housing is half-filled with a transparent liquid having a specified viscosity and index of refraction and half-filled with air. Light beams emitted from the sources are refracted upon passing through the boundary between the air and the liquid. As the orientation sensor rotates with respect to the vertical axis, the changing refraction angle of the light beam causes the detector to sense changing intensities of light, which are representative of the angle of rotation. Multiple light source/detector pairs spaced within the spherical housing allow measurement of direction and magnitude of angular change. Integral with the input device is a speaker independent voice control circuit which recognizes short isolated command words ending in voiced or fricative sounds for controlling display functions.