Abstract: The invention concerns a device for data entry into a portable object, in particular a watch, with display screen comprising a control button (1) consisting of an elastic mass (2) wherein is housed a permanent magnet (3) and a positioning analogue magnetic sensor (4) with Hall effect for example, arranged inside the object opposite to and spaced apart from said control button (1), said sensor being adapted to measure the movements of the magnet (3) in at least one direction for data entry. The control button (1) is arranged in a blind housing (7) of a non-magnetic wall (5) of the object structure, to be mechanically uncoupled from the sensor, said wall not in contact with said sensor acting as sealing protection for the sensor.