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.