Described herein is a car entertainment and navigation system that includes a user interface controller, a detecting circuit, and a selection circuit. The detecting circuit includes a selection circuit, capacitance-sensing circuitry to determine a location of a touch proximate to one or more electrodes of the touch screen display based on capacitance measurements of a plurality of electrodes of the touch screen made during a first mode of operation of the detecting circuit, and user-detecting circuitry to determine a location of a user corresponding to the touch based on signal measurements of a capacitively-coupled signal at the one or more electrodes made during a second mode of operation of the detecting circuit. The selection circuit is configurable to selectively couple the capacitance-sensing circuitry to the plurality of electrodes during the first mode and selectively coupling the user-detecting circuitry to the one or more electrodes during the second mode.