Summary Hey- This is a simple attachment to test and see the 43.3:1 Differential gearbox in action!, if you haven't seen that yet, go check it out! This is the ONLY gearbox compatible with this demo arm, unless you mess with the scaling: http://www.thingiverse.com/thing:2081324 Overview and Background This is Just a Mount and arm to demonstrate demonstrate the differential planetary gearbox. Lesson Plan and Activity I don't have a Lesson Plan... Materials Needed You will need a 3D printer, Fillament, a Nema 17 Stepper motor, The Gearbox ( http://www.thingiverse.com/thing:2081324 ), the Nema Mount, The Demo Mount and Arm, 4 Allen Head M3 Screws, a long allen wrench, and a lot of time :) Skills Learned Gear Ratios Gearing Torque Arduino Stepper Motors Assembly