From description:
A platform (5cm radius) and a fitting 3-arm-actuator which is connected to a stepper motor with a 5mm coupler and runs on a base made of foamboard.
The platform has 3 holes to fix small bearings for smoother moving.
Controlled with an Arduino, a stepper motor board and a gear stepper motor with 2048 steps per round.
There are no detailed instuction, but it doesn't look too complicated.
http://www.thingiverse.com/thing:96047