Wireless interface (11) for a planar sensor system, which planar sensor system comprises an electrically conductive planar sensor, which comprises a number of adjacent electrically conductive areas (1), an operating unit/control unit (19), and also a connection for connecting the sensor to an operating device/control device, characterized in that the wireless interface (11) is an independent display device, which comprises a display (12), a control unit (14), a power source, and also a short-range radio (16), and which display can be controlled position- dependently in the area of a sensor (41, 42) such that - the position of the display device is determined by means of the planar sensor, - the information on the display in predefined positions is changed by forming by means of short-range radio (16) a wireless connection with the antenna (28) arranged in connection with the planar sensor under the display device, and by giving by means of the antenna (28) an excitation for displaying the information (INFOl - INFO3) predefined for the position in question on the display of the display device.