A mixing device is disclosed that includes a base, a magnet post configured for insertion into a hollow portion of a reagent container, a stationary magnet mounted on the magnet post, and a mixing ball including a ferromagnetic material provided in the reagent container, wherein the reagent container may be moved back and forth on the magnet post. Another mixing device is disclosed that includes a housing, a drive mechanism, a drive magnet mechanically coupled to the drive mechanism, a coupling magnet magnetically coupled to the drive magnet, a mixing ball including a ferromagnetic material provided in a reagent container, and a controller, wherein the controller is configured to control the drive mechanism to cause the drive magnet to move, and wherein the motion of the drive magnet induces a first corresponding motion in the coupling magnet, and wherein the first corresponding motion of the coupling magnet induces a second corresponding motion in the mixing ball,