[Oleg] of Circuits@Home and maker of the USB Isolation Board and the USB Host Shield has a new, two-part hack for his chemistry set. In Part 1 of this hack, [Oleg] discusses the method he uses to make a stir bar spin and what types of stir bars work the best. Part 2 discusses the motor control code and circuit. Given the ample amount of capability leftover in the Arduino he used, we would like to see this stirrer paired with a heating element to have a complete hotplate/stirrer. What do you think you could do with or to improve this device?