a motor;

a lifter configured to be rotatable by the motor about a rotational axis;

a biasing member configured to store a force for driving a fastener, wherein the lifter is configured to release the force;

a piston configured to be urged by the force of the biasing member towards a bottom-dead-center position to drive the fastener into a workpiece;

a magnet coupled to the lifter for rotation with the lifter, the magnet formed as a single piece, the single piece including a first pair of poles including a first north pole face and a first south pole face, the single piece further including a second pair of poles including a second north pole face and a second south pole face, wherein the first north pole face is adjacent the second south pole face, and wherein a pole junction is defined between the first pair of poles and the second pair of poles;

a sensor configured to detect the pole junction; and

a controller configured to control the motor based on detection of the pole junction.