15 mm Stepper Motor with Rod

This tiny stepper motor drives a threaded rod directly, and the slider riding on it turns rotation into precise linear movement, the same arrangement used in camera-lens focusing and optical-drive mechanisms. It is a two-phase, four-wire bipolar motor, so it needs a stepper driver such as an A4988 or DRV8833 rather than a direct connection to a microcontroller pin. Run it at low current to suit its small coils, and check the rated voltage and travel length of your unit before setting up the driver. It suits miniature linear stages, robotics demos, automated valves and teaching how stepper motors work.