A homopolar motor made with a battery cell and a coiled wire. DIY simple homopolar motor made with a drywall screw, a battery cell, a wire, and a disk magnet. The magnet is on the screw head. The screw and magnet make contact with the bottom of the battery cell and are held together by the magnet's attraction. The screw and magnet spin, with the screw tip acting as a bearing. A homopolar motor is