A set comprising an input device, in particular for computers, and a receiving unit, wherein the receiving unit comprises at least two, preferably at least three, cameras by means of which light-emitting elements can be captured, wherein the longitudinal axes of the cameras each have a distance d from each other and include an angle of <180° in relation to each other, wherein the receiving unit constitutes a head-mounted unit, which is adapted to be fixed to the head of a user, and wherein the input device and the receiving unit provide a possibility of interaction with digital and mixed and/or augmented reality contents, wherein the input device includes at least three light-emitting elements which are arranged at a distance from each other, and wherein the receiving unit is used for position detection, wherein the input device constitutes an input unit, characterized in that the input device includes a pointing tip, wherein the input device includes an inertial measurement unit, wherein the set is configured to utilize tilt and rotation data from the inertial measurement unit of the input device in addition to the position information of the cameras to determine the position of the pointing tip of the input device, in that the at least three light-emitting elements are three IR LEDs (4, 4', 4"), wherein the three IR LEDs (4, 4', 4") are located on a rear end face at the rear end of the input device, the rear end face being opposite to the pointing tip, and in that the input device includes a vibration unit, wherein the set is configured to haptically indicate to the user a collision of the input device with a digital content by using different vibration modes. wherein the receiving unit comprises at least two, preferably at least three, cameras by means of which light-emitting elements can be captured, wherein the longitudinal axes of the cameras each have a distance d from each other and include an angle of <180° in relation to each other, wherein the receiving unit constitutes a head-mounted unit, which is adapted to be fixed to the head of a user, and wherein the input device and the receiving unit provide a possibility of interaction with digital and mixed and/or augmented reality contents, wherein the input device includes at least three light-emitting elements which are arranged at a distance from each other, and wherein the receiving unit is used for position detection, wherein the input device constitutes an input unit, characterized in that the input device includes a pointing tip, wherein the input device includes an inertial measurement unit, wherein the set is configured to utilize tilt and rotation data from the inertial measurement unit of the input device in addition to the position information of the cameras to determine the position of the pointing tip of the input device, in that the at least three light-emitting elements are three IR LEDs (4, 4', 4"), wherein the three IR LEDs (4, 4', 4") are located on a rear end face at the rear end of the input device, the rear end face being opposite to the pointing tip, and in that the input device includes a vibration unit, wherein the set is configured to haptically indicate to the user a collision of the input device with a digital content by using different vibration modes.