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.