Order the motors and servo before printing so you can check the printed fits against the hardware you receive.
Electronics
The robot's controller is the Alfredo NoU3. If you already have one from Making a motor move, you're set. Otherwise, add one to the order:
Parts list
Alfredo NoU3×1
USB-C data cable×1
Bluetooth Xbox controller×1if neededMotion
Two small gearmotors drive the wheels, and one servo powers the arm.
Parts list
N20 micro gearmotor×2
43 mm rubber wheel for N20 shaft×2
MG996R servo with star-shaped horn and center screw×1Use the star-shaped horn supplied with the MG996R to drive the arm linkage. It is not a printed starter bot part, so choose a servo package that includes the horn and its center screw.
⚠️ Make sure your N20s come with wires. Many listings ship the bare motor, which has tiny solder tabs. Buy a version with leads already soldered on, long enough to reach the NoU3 with the deck loose (or be ready to solder your own).
N20 listings vary in gear ratio, shaft length, and lead length; the listed voltage does not matter. Match the body and shaft dimensions in the CAD before ordering. The first tested build still needs to establish a preferred gear ratio.
One more buy-day tip: motors and 43 mm wheels are often sold together as pairs, so one combo listing can cover both rows.
Power
For a league-legal robot, use a 2S battery and its charging gear. The Battery options page covers the pack, charger, safety gear, and barrel-jack adapter.
Hardware and filament
The printed parts use M3 hardware. Some joints take screws and heat-set inserts; moving joints use bolts and nuts. The assembly pages explain how to test-fit each joint before committing to an insert.
Parts list
M3 heat-set inserts, 5 mm length×1
M3 screws, assorted lengths×1
M3 bolts with nuts, assorted lengths×1
PLA filament, 1 kg spool×1if you're outTools
- A 3D printer (a school, library, or makerspace printer works fine)
- A soldering iron for pressing heat-set inserts into the prints
- Small Phillips and hex screwdrivers
When the orders are in, head to the printer.
Product-identification images: N20 from DFRobot, 43 mm wheel from DFRobot, and MG996R from TowerPro. Xbox Wireless Controller Model 1708 photo by MiNe (CC BY 2.0); PLA photo by Richardspa (CC0). Additional product-identification images: M3 inserts from Spool3D, screw set from Quartz Components, and bolt-and-nut set from Rotor Riot. Images were resized and placed on white backgrounds.