Abstract: Control knob comprising a mobile part (3) capable of being actuated manually and linked with an electromechanical transducer (7). The knob also comprises a metal surface (15) arranged in the vicinity of the mobile part and means to measure the capacitance of the metal surface so that the presence of a finger in the vicinity of the mobile part can be detected.

Abstract: Onboard control system (1), particularly for motor vehicles, comprising a control device (9), buttons (13, 15), and a computer (5) capable of responding to the actuation of the buttons (13, 15) by executing the onboard device (3) control functions selectively, characterised in that the computer (5) is capable of controlling a display device (11) with a view to displaying the buttons (13, 15) and responding to the actuation of at least a first button (13) by reassigning onboard device (3) control functions to second buttons (15) while refreshing the display of the second buttons (15) to indicate the function associated therewith.