A method for controlling operations of a portable device through a touch-free user input in the portable device having a projector module is provided. A plurality of discrete energy interactions is received in a plurality of detector voxels. The path control module controls the wire winding and the power source to form a first loop to produce a first magnetic field or a second loop to produce a second magnetic field by controlling the path switching module. At least one optical filter may be disposed between the substrate and the focal plane array so as to pass only coating transparent wavelengths of the reflected light along an optical path between the infrared light source and the focal plane array thereby visually revealing irregular structural features of the substrate as at least one image. Second edges are formed in positions extended in the direction of movement of the magnetic tape from each end of the sliding surface and come in contact with the magnetic tape.