Abstract: A combined mouse and track ball are contained within an ergonomically designed housing or shell. The shell is curved to fit comfortably within the palm of the hand of an operator so that the forefinger and thumb are opposed to each other in a prehensile position. A single shell is operable by a left-handed or right-handed operator by rotation of a switch to change the alignment of the sensor pickups engaging the roller ball of the combined mouse and track ball. At least one switch plate extends across an upper surface of the shell for depression by a forefinger of the operator. The switch plate is pivoted about a central fulcrum so as to have a cursor shifted to a position above an icon located on a computer screen for depression of the switch plate and initiation of the computer function indicated.

Abstract: A touch screen display is automatically calibrated during periods of active use or extended periods of non-use. Calibration contacts are cemented or embedded to the surface of a touch sensitive panel, and electrically connected to a reference during calibration. The reference is either electrical ground or a resistive, capacitive, or inductive load.