Here's a motor + gearbox + position sensor + controller module assembled:
Cute feature: The FETs on the bottom of the board heatsink to the flat spot on the gearbox.
At the other end is a small diametrically magnetized cylindrical magnet, glued to the rotor, and MA700 chip sensing magnet orientation.
Here's it spinning with the gearbox open. Nice sound of dry-running spur gears: