Electrical device, in particular a telecommunication device having a projection unit and method for operating an electrical device

A method for operating an electrical device having a projection unit and a detection unit, comprising:

• projecting, by a projection unit, image information along a projection beam path onto a projection surface located outside the electrical device, wherein the image information is projected onto the projection surface (i) with the aid of at least one optical element in the projection beam path for sequentially constructing an image, and (ii) for momentarily spatially limiting the projection relative to the total area of the image information on the projection surface;
• and
• detecting, by a detection unit, a movement of the projection surface taking place during projection in the form of one of a displacement or a rotation of the projection surface relative to the projection unit, wherein the detection unit detects the movement of the projection surface with the aid of a reflection signal based on a reflection on the projection surface, the reflection signal passing along a detection beam path, and wherein the detection beam path and the projection beam path coincide at least in the area of the at least one optical element.