Abstract: Identifying a tool touching a touchscreen device. A touch location of a tool on a touch-sensitive surface is received from a touchscreen controller. Based on the touch location, one of a plurality of electrodes disposed at locations across the touchscreen is selected and an electric circuit is enabled. The electric circuit includes a signal generator attached to the tool that transmits a modulated identification (ID) signal, a parasitic capacitance path between the signal generator and the selected electrode, a demodulator connected to the selected electrode that receives the ID signal, a resistive layer connected to the demodulator, covering the touch-sensitive surface, and a resistive path through the tool to the signal generator. The demodulator demodulates the modulated ID signal to recover a bit sequence. The tool is identified, based on the recovered bit sequence.

Abstract: A system for identifying a tool touching a touchscreen device includes a touch-sensitive surface that generates a signal in response to a touch from a tool touching the surface; a touchscreen controller that receives the signal from the touch-sensitive surface and determines the location of the touch; logic to select, based on the touch location, one of a plurality of electrodes disposed across the touch-sensitive surface; logic to enable an electric circuit that includes a signal generator attached to the tool that transmits a modulated ID signal; a parasitic capacitance path between the signal generator and the electrode; a demodulator connected to the electrode that receives and demodulates the modulated ID signal to recover a bit sequence; a resistive layer, connected to the demodulator, covering the touch-sensitive surface; a resistive path through the tool to the resistive layer; and logic that identifies the tool, based on the recovered bit sequence.

Abstract: Identifying a tool touching a touchscreen device. A touch location of a tool on a touch-sensitive surface is received from a touchscreen controller. Based on the touch location, one of a plurality of electrodes disposed at locations across the touchscreen is selected and an electric circuit is enabled. The electric circuit includes a signal generator attached to the tool that transmits a modulated identification (ID) signal, a parasitic capacitance path between the signal generator and the selected electrode, a demodulator connected to the selected electrode that receives the ID signal, a resistive layer connected to the demodulator, covering the touch-sensitive surface, and a resistive path through the tool to the signal generator. The demodulator demodulates the modulated ID signal to recover a bit sequence. The tool is identified, based on the recovered bit sequence.

Abstract: A system for identifying a tool touching a touchscreen device includes a touch-sensitive surface that generates a signal in response to a touch from a tool touching the surface; a touchscreen controller that receives the signal from the touch-sensitive surface and determines the location of the touch; logic to select, based on the touch location, one of a plurality of electrodes disposed across the touch-sensitive surface; logic to enable an electric circuit that includes a signal generator attached to the tool that transmits a modulated ID signal; a parasitic capacitance path between the signal generator and the electrode; a demodulator connected to the electrode that receives and demodulates the modulated ID signal to recover a bit sequence; a resistive layer, connected to the demodulator, covering the touch-sensitive surface; a resistive path through the tool to the resistive layer; and logic that identifies the tool, based on the recovered bit sequence.