A stepper motor and controller are provided for controllably adjusting the angular displacement of a rotor. The stepper motor has a plurality of stator coils that are configured to effect rotation of the rotor upon application of a voltage thereto. The stepper motor further includes one or more sensing coils, where rotation of the rotor generates an induced voltage in the one or more sensing coils. A controller is included for processing the induced voltage signals, and is configured to output a constant vector value that does not change in value where the induced voltage signals are indicative of the rotor rotating in a continuous manner, and to output a diverging vector value where the induced voltage signals are indicative of the rotor being inhibited from rotating. The controller is configured to determine the rotor's angular displacement from the constant vector value, and to detect occurrence of the rotor being inhibited from rotating from a diverging vector value.