The primary function of the microdrive is to move an electrode bundle parallel to its own long axis.

In the exploded view the (black) motor assembly rotates a (gold) threaded leadscrew turning inside a small shuttle. Electrodes attached to the shuttle move with it along the leadscrew. One or more electrodes are mounted to pass alongside the motor and exit a small hole in the (purple) base. A thin flexible wire (not shown) runs from an electrode to the PCB and connector.

The base, shuttle, and cover are low cost disposable parts. The body, motor assembly, leadscrew, printed circuit board, connector, and wiring are preserved for reuse.

Inside the motor assembly, a gearbox translates many turns of the internal motor shaft into one turn of the output shaft and leadscrew. The motor turns in six steps, but hundreds of steps are required to turn the leadscrew. The leadscrew is very finely threaded, so that it takes many turns to move the shuttle 1 mm along the leadscrew. Altogether, this means that one motor step moves the shuttle and electrode(s) by a fraction of one micron.

RP Metrix uses a commercially available motor assembly, not designed for this purpose. It is lightweight but fragile. For this reason, we offer kits so the investigator can trade labor for cost, and have parts and skills on site to quickly replace the occasional failed microdrive in the middle of an experiment.