What SO-101 Robot Arm can do.
An open, 3D-printable leader-and-follower robot arm system designed to collect demonstrations and train real-world AI policies with LeRobot.
Leader–follower teleoperation
A six-axis leader arm provides demonstrations that the matching follower arm can reproduce through LeRobot.
12Real-world robot learning
LeRobot supplies the model, dataset and control workflow used to collect demonstrations, train policies and deploy them on the arm.
3Cross-unit calibration
The documented calibration process aligns physical joint ranges so a policy trained on one calibrated unit can transfer to another.
2From software intent to physical behavior.
This system view follows the documented functional blocks and keeps unknown internals explicit.
SO-101 leader arm
Captures the operator's joint motion for teleoperation and demonstration collection.
SO-101 follower arm
Executes teleoperated actions and trained policy outputs in the physical workspace.
MotorBus electronics
Connects each daisy-chained servo arm to the host computer over USB and supplies motor power.
LeRobot host stack
Configures and calibrates the arms, records datasets, trains policies and sends actions to the follower.
The documented physical stack.
Documented partsSix actuators drive the follower; one drives the leader shoulder-lift joint.
Drives the leader wrist-flex, wrist-roll and gripper joints with 1/147 gearing.
Forms the bases, links, wrists, leader handle and follower gripper around the servos.
Build and commission an SO-101 leader–follower system
A scan-friendly path derived from the documented construction sequence.
- Parts from the official two-arm bill of materials
- FDM printer or printing service for the official STL files
- Host computer with USB ports
- LeRobot installation with the Feetech extra
- Phillips #0 and #1 screwdrivers
- Small screwdriver or tool for support removal
- 3D-printer bed preparation tools
- Labels or marker for identifying motors
Disconnect power while changing servo-bus wiring, verify the selected servo voltage and power supply, and keep hands clear during motion tests.
Source electronics and print the structure
Acquire the documented two-arm BOM and print the leader and follower STL sets with the repository's FDM guidance.
- Choose the documented servo voltage and matching power supplies
- Print and fit-check the official leader and follower parts
- Remove supports and organize hardware by arm
Install LeRobot and configure the servos
Install the Feetech integration, identify each USB bus and assign the six motor IDs on each arm.
- Install LeRobot and the Feetech extra
- Find and label the leader and follower USB ports
- Set each servo ID and baud rate one motor at a time
Official project image · Apache-2.0Assemble the six-joint arms
Build the leader and follower around their ordered servos, routing the daisy-chain cables as each joint is closed.
- Install the base and shoulder joints
- Assemble elbow and wrist joints with the documented gear ratios
- Attach the leader handle and follower gripper
Calibrate leader and follower
Move every joint through its range so LeRobot can map matching physical positions across the two arms.
- Run follower calibration
- Run leader calibration
- Check that corresponding joint positions align
Teleoperate, record and train
Verify leader–follower control, then use the real-world robot workflow to record demonstrations and train a policy.
- Test teleoperation with conservative motion
- Connect a task camera and record demonstrations
- Train and evaluate a LeRobot policy
Rights-aware build documentation.
The reviewed SO-ARM100 hardware repository and LeRobot software repository are Apache-2.0. Two SO-101 images stored in the hardware repository's media directory are displayed with Apache-2.0 attribution; all other official media remains link-only until asset-level provenance is recorded.
The documented software and intelligence layer.
Read the evidence without leaving SauceSnap.
Inspect captured facts and their original locations before opening an external source.
1Standard Open SO-100 & SO-101 ArmsTheRobotStudio · 3 captured factsPreview
Inspect captured facts and their original locations before opening an external source.
- Repository licenseApache-2.0verified
- Sourcing Parts — Parts For Two Arms (Follower and Leader Setup)12 STS3215 servos, 2 motor control boards, USB-C cables, 2 power supplies, 4 table clamps and a screwdriver set; official US total $229.88verified
- Printing the Parts — Step 4Official leader and follower STL sets are provided for FDM 3D printingverified
2SO-101 assembly and calibrationHugging Face · 4 captured factsPreview
Inspect captured facts and their original locations before opening an external source.
- Step-by-Step Assembly Instructions6 × STS3215 7.4 V servos with 1/345 gearingverified
- Leader-Arm Axis — Motor — Gear Ratio1 × 1/345, 2 × 1/191 and 3 × 1/147 STS3215 servosverified
- Configure the motors — Set the motor IDs and baud ratesEach arm uses a USB motor-bus controller; the six servos receive unique IDs and a shared baud rate before daisy-chain assemblyverified
- CalibrateCalibration aligns matching physical positions and is documented as enabling a neural network trained on one robot to work on anotherverified
3LeRobotHugging Face · 2 captured factsPreview
Inspect captured facts and their original locations before opening an external source.
- Repository licenseApache-2.0verified
- README — models, datasets and tools for real-world roboticsProvides models, datasets and tools for controlling real-world robots, recording demonstrations, training policies and deploying actionsverified