A step motor includes a plurality of stator cores. Each of the stator cores have a coil unit coiled therearound. The step motor includes a rotor that includes a rotation shaft and a plurality of permanent magnets and is configured to rotate by magnetic interaction between the stator cores and the permanent magnets. The step motor also includes a plurality of conducting parts on one cross-sectional surface of the rotor. The step motor further includes a printed circuit board (PCB) including electric elements that are arranged at certain positions and are disposed to face the conducting parts. The conducting parts and the electric elements are configured to electrically or magnetically interact as the rotor rotates to change electrical signals generated by the electric elements.