The invention is based on a device (10) with a sensor, which is guided with one hand (20, 22) over a surface (14) and in which the data detected are displayed by a display unit (38). The invention proposes that grasping surfaces (40, 42) for the hand (20, 22) be positioned on two approximately diametrically opposed sides of a grip (12), at least one of which sides has a sensor (26, 28, 30, 32) that detects the number of fingers (20, 22) resting against this grasping surface (40, 42).
