I want to make a shaft rotate in 21 discrete steps, from a motor that is turning smoothly.
I am thinking of some kind of simplified clock escapement type of mechanism. Or non circular gears.
I know it could be done by programming a stepper motor. But it will be easier and more fun for me to do it mechanically with 3D printed nylon parts.
This is for a low torque low speed application. About 1 rpm and less than 0.1 Nm torque.