In a data-input device an actuator element that can be manually actuated, and a sensor mechanically coupled to the actuator element. The sensor is formed in a body of semiconductor material housing a first sensitive element, which detects the actuation of the actuator element and generates electrical control signals. The first sensitive element is a microelectromechanical pressure sensor, formed by: a cavity made within the body; a diaphragm made in a surface portion of the body and suspended above the cavity; and piezoresistive transducer elements integrated in peripheral surface portions of the diaphragm in order to detect its deformations upon actuation of the actuator element.