At it’s heart, it’s a straightforward design, using a linear rail and a leadscrew driven by a stepper motor. Control is via an Arduino Nano, with a few push buttons and a 16 x 2 LCD display ...

Mechaduino is a board that sits on a regular stepper motor and turns it into a servo with a closed loop control of 0.1degree.

Oriental Motor of Japan is offering stepper motors with battery-free multi-turn absolute position encoding that can ride through power-loss.