The Printed Arm
The workhorse of Physical AI: a fixed-base arm that picks a block and places it on a target. Real datasets, real imitation learning, the platform behind the checkpoint and VLA courses.
Drive it in real physics.
The four-part build starts with this: the design as a real MuJoCo twin you can pilot right now on Play. Take the controls, then build the body that runs it.
Grasp with the twin
A fixed-base manipulator in real physics. Fly the gripper in straight Cartesian lines through the Jacobian, close the fingers, and watch the world through a wrist camera.
Fly the gripper in straight Cartesian lines; close to grasp, through a wrist camera.
▶ Drive the twin on Play ↗Four parts, one loop.
Body, brain, driver, policy. The design forces no single board, only that whatever you pick can take the commands and run the policy.
A printed low-cost arm
A LeRobot-class printed arm: five or six hobby-servo joints and a gripper on a weighted base, the de-facto open manipulation platform, printable at home.
From cheap to visual
A servo bus and, when you want visual grasping, a camera and a brain to see the block. Pick from the options below.
Browser → servo bus
Joint targets stream to the servo bus over the driver registry, the same path LeRobot uses for teleoperation and dataset capture. The arm becomes the hands for a real policy.
Demos → imitation → ship
Teleoperate to collect demonstrations, train by imitation, then run the policy. The identical joint stream drives the twin and the real arm, the bridge to the checkpoint course.
Ways to power the same body.
Cheapest to heaviest. Every one drives the identical printed body and runs the same policy.
Servo bus + ESP32-S3 / CyberBrick
~$20Drives the joint bus for teleoperation and playback, with the policy on your laptop.
Raspberry Pi 5 + AI Camera
$150+Visual grasping on-board: see the block, close the gripper.
NVIDIA Jetson Orin Nano
$249Run a real VLA (SmolVLA-class) on the arm itself.
Full specs and roles for every board: Digital Brains →
Open robots like this one.
The Maker Atlas maps real, open Physical-AI robots to each of our builds. These are kin to this one, open a profile to trace its boards, sensors, and source.
Koch v1.1
The low-cost Dynamixel leader/follower arm that seeded SO-100; LeRobot-native. Apache-2.0.
In the wildLeRobot LeKiwi
A holonomic mobile base + SO-101 arm = a ~$1k open mobile manipulator on a Raspberry Pi 5, dual cameras. LeRobot.
In the wildElephant myCobot 280
The smallest 6-DOF desktop cobot; ESP32 / Pi / Jetson variants, open pymycobot SDK + ROS. (Molded body, open API.)
In the wildROBOTIS OpenManipulator-X
The canonical ROS perception arm, Dynamixel + RealSense D435 pick-and-place out of the box. Apache-2.0.
In the wildBCN3D Moveo
A classic fully-3D-printed 5-axis education arm (steppers + printed gears); one of the most-built open arms. GPLv3.
In the wildPAROL6
An industrial-grade 6-DOF printed desktop arm (closed-loop steppers, 0.2 mm); Hackaday-Prize finalist. GPL.
In the wildLEAP Hand
A ~$2k low-cost 16-DOF anthropomorphic dexterous hand for robot learning, fully FDM-printable. MIT (CMU).
In the wildDexHand
An entirely 3D-printed 16-servo dexterous humanoid hand, ~$300 in parts, open. (The Robot Studio / Rob Knight.)
In the wildAmazing Hand
A fully 3D-printed 8-DOF, 4-finger hand under €200 with all actuators internal (Feetech SCS). Apache/CC. (Pollen.)
In the wildSO-100 / SO-101 arm
The ~$100–500 open, printable teaching arm, the de-facto low-cost manipulation platform.
In the wildYale OpenHand
Yale's family of open, mostly-printed underactuated hands (Model O / T42 / Q), the reference open printable dexterous-hand project. OSHW.
In the wildORCA Hand
ETH Zürich's 17-DOF tendon-driven hand with integrated tactile sensing, buildable in a day. MIT/CC, <2000 CHF.
In the wildRUKA
NYU's tendon-driven underactuated hand with a learned controller (no joint sensors) for robot learning + teleop. Open, <$1,300.
In the wilde-NABLE
The largest open community of free 3D-printed prosthetic hands, body-powered; sensorized/myoelectric forks add sEMG + Arduino. Mostly CC.
In the wildMobile ALOHA
Stanford's low-cost bimanual teleop + imitation-learning platform (Mobile ALOHA adds a wheeled base), printed mounts on Trossen arms + 4 cameras. MIT.
In the wildXLeRobot
A ~$660 open dual-arm mobile home robot, two SO-101 arms on an IKEA cart, LeRobot policies, Bambu-printable. Open.
See how they all connect: the Maker Atlas →
Live now: the twin. In progress: the physical unit.
The sim twin on this page is real and live today. The printable body and the driver are specced against the sim-to-real registry; the first physical unit is being assembled, and the STL pack and step-by-step land here the moment it's verified on real hardware, not before.
Design its body, program its brain.
Take this build into the Studio: model and export its printed parts on the CAD kernel, and write the MicroPython that runs on its board. Both open as full-screen workspaces.