Computer input stylus method and apparatus

Abstract

A system comprising a conductive stylus used in conjunction with a capacitance sensitive touch pad, said system providing at least two different signals to an associated computer system. The stylus is a pen-like device having an actuable switch which when actuated substantially increases the capacitive disturbance caused by the conductive stylus on the touch pad. Before actuation, the stylus creates a capacitive disturbance sufficient for circuitry in the touch pad to measure as crossing a first predefined capacitive disturbance threshold when the foam covered conductive stylus tip is brought in contact with the surface of the touch pad. When the switch is actuated, the capacitive disturbance measured by the touch pad increases sufficient to cross a second predefined capacitive disturbance threshold. An associated computer program for drawing on a computer display places a cursor on the display when the first threshold is crossed. The computer program begins drawing on the display beginning at the cursor location when the switch is actuated causing the second threshold to be crossed. Placing a conductive foam cover over the conductive stylus tip results in the measured capacitive disturbance being amplified to thereby increase the magnitude of the capacitive disturbance of the stylus.