Open-Source Robot Hardware
The explosion of open-source hardware has dramatically lowered the barrier to robot learning research. From $110 desktop arms to $32K mobile dual-arm platforms, researchers now have a rich set of choices. This article compiles the current mainstream open-source robot hardware platforms.
Platform Overview
| Platform | Type | Cost | DOF | Key Features | Developer |
|---|---|---|---|---|---|
| ALOHA | Desktop dual-arm teleoperation | ~$20K | 2x6+2 grippers | Bilateral teleoperation, original ACT policy platform | Stanford |
| ALOHA 2 | Desktop dual-arm teleoperation | ~$20K | 2x6+2 grippers | Engineering-improved ALOHA, DeepMind companion | Google DeepMind |
| Mobile ALOHA | Mobile dual-arm | ~$32K | 2x6+mobile base | ALOHA on mobile base, whole-body teleoperation | Stanford |
| UMI | Gripper data collection tool | ~$200 | 1 gripper | iPhone ARKit tracking, portable data collection | Columbia |
| GELLO | Joint-space teleoperation device | ~$200 | Matches target arm | Kinematic matching, direct joint-space mapping | Berkeley |
| LEAP Hand | Dexterous hand | ~$2K | 16 | 3D printed, direct drive, RL-friendly | CMU |
| Koch v1.1 | Low-cost single arm | ~$250 | 6+gripper | Official LeRobot support platform | Jess Moss / Community |
| SO-100 | Low-cost single arm | ~$110 | 5+gripper | Currently the cheapest research-grade arm | HuggingFace / Community |
| Open Manipulator X | Single arm | ~$500 | 4+gripper | Dynamixel driven, native ROS2 support | ROBOTIS |
Detailed Introductions
ALOHA / ALOHA 2
ALOHA (A Low-cost Open-source Hardware System for Bimanual Teleoperation) was released by Stanford's Zhao et al. in 2023 and is the de facto standard for dual-arm manipulation research.
Hardware Components
| Component | Specification |
|---|---|
| Follower Arms | 2x ViperX 300 6DOF (Interbotix) |
| Leader Arms (Teleop) | 2x WidowX 250 6DOF (Interbotix) |
| Gripper | Parallel gripper |
| Motors | Dynamixel XM/XH series |
| Cameras | 4x Logitech C922 (top + wrist) |
| Control Frequency | 50Hz |
| Frame | 80/20 aluminum extrusion |
Bilateral Teleoperation Principle
The operator (Leader) and follower use robot arms with identical kinematic structure. The operator moves the Leader arm, and joint angles are mapped in real time to the Follower arm:
Since both arms have identical kinematics (joint-space mapping), no inverse kinematics computation is needed, and the mapping is precise with minimal latency.
ALOHA 2 Improvements
Google DeepMind made engineering improvements on top of ALOHA:
| Improvement | Description |
|---|---|
| Better camera mounting | More stable, better viewing angle coverage |
| Improved gripper | Wider grasp range |
| Better cable management | Reduced interference during joint motion |
| Data collection software | Compatible with RT-2, ALOHA Unleashed algorithms |
Associated Algorithms
| Algorithm | Paper | Description |
|---|---|---|
| ACT | Learning Fine-Grained Bimanual Manipulation | CVAE + Transformer, original ALOHA paper |
| Diffusion Policy | Diffusion Policy | Diffusion model generates action sequences |
| ALOHA Unleashed | — | Google DeepMind large-scale training |
Build Notes
- Assembly time: ~2-3 days (including 3D printing wait time)
- Key tool: Dynamixel Wizard 2.0 (set motor IDs and baud rates)
- Common issues: Leader/Follower zero-point calibration, cable routing to prevent tangling
- GitHub: https://github.com/tonyzhaozh/aloha
Mobile ALOHA
Adds a mobile base to ALOHA for whole-body teleoperation.
| Component | Specification |
|---|---|
| Base | AgileX Tracer |
| Robot Arms | 2x ViperX 300 |
| Teleoperation | 2x WidowX 250 + base joystick |
| Additional Sensors | IMU, wheel odometry |
| Total Cost | ~$32K |
Research Significance: Demonstrated the feasibility of "whole-body teleoperation" — the operator simultaneously controls base movement and dual-arm manipulation, collecting mobile manipulation data.
Build Notes
- Mechanical mounting between base and dual arms requires custom mounting plates
- Power system needs unification (base battery powers both arms and computing platform)
- GitHub: https://github.com/MarkFzp/mobile-aloha
UMI (Universal Manipulation Interface)
UMI is an ultra-low-cost data collection solution proposed by Columbia University. The core idea is tracking the 6-DoF trajectory of a hand-held gripper using iPhone.
Working Principle
- 3D print a hand-held gripper (with iPhone mount)
- iPhone uses ARKit to provide 6-DoF pose tracking
- During collection, the operator manipulates the hand-held gripper in real scenes
- Record gripper pose trajectory + open/close state
- During playback, map trajectory to target robot
Core Advantages
| Advantage | Description |
|---|---|
| Ultra-low cost | ~$200 (iPhone not included) |
| Platform-agnostic | Data can be replayed on different robots |
| Natural operation | Operator holds directly, no teleoperation learning needed |
| Scalable | Anyone can participate in data collection |
Limitations
- Depends on iPhone ARKit accuracy (~1cm position error)
- No force feedback, not suitable for precision assembly
- Requires Cartesian control capability on the target robot
Build Notes
- 3D printed parts: Gripper body + iPhone mount (STL files open-sourced)
- Required iPhone: iPhone supporting ARKit (iPhone 12 and above recommended)
- GitHub: https://github.com/real-stanford/universal_manipulation_interface
GELLO
GELLO is a low-cost joint-space teleoperation device developed by Berkeley, building a kinematically scaled-down teleoperation handle for the target robot.
Design Philosophy
| Feature | Description |
|---|---|
| Joint count | Same as target robot (6 or 7) |
| Motors | Dynamixel XL330-M077 (~$25 each) |
| 3D printed | All links fully 3D printed |
| Total cost | ~$200 |
| Mapping method | Direct joint-space mapping (no IK needed) |
Adapted Robots
| Target Robot | GELLO Version |
|---|---|
| Franka Panda | 7-DOF GELLO |
| UR5 | 6-DOF GELLO |
| xArm | 6-DOF GELLO |
| Koch | 6-DOF GELLO |
Build Notes
- Link proportions need customization for the target robot (open-source repository provides multiple versions)
- Motor ID setup and zero-point calibration are critical steps
- GitHub: https://github.com/wuphilipp/gello_software
LEAP Hand
LEAP (Low-cost, Efficient, and Agile Prosthetic) Hand is an open-source dexterous hand developed by CMU and is currently the most active open-source dexterous hand platform.
| Feature | Specification |
|---|---|
| DOF | 16 DOF (4 fingers x 4 joints) |
| Actuators | 16x Dynamixel XC330-T288-T |
| Drive Method | Direct drive (no tendons) |
| Material | 3D printed (PLA/PETG) |
| Weight | ~500g |
| Grip Force | ~15N fingertip force |
| Control Frequency | 200Hz |
| Cost | ~$2,000 |
Research Value:
- 16 DOF provides the redundancy needed for dexterous manipulation
- Direct drive simplifies control (no tendon breakage risk)
- Low cost makes multiple experimental setups feasible
- Adopted by multiple research groups for dexterous manipulation RL research
Build Notes
- Print time: ~20-30 hours (all parts)
- Assembly time: ~1 day
- Key note: Motor wiring needs to be compact; finger joint alignment precision affects grasp quality
- GitHub/Homepage: https://leap-hand.github.io/
Koch v1.1
Koch is a low-cost 6-DOF robot arm designed for the LeRobot ecosystem.
| Feature | Specification |
|---|---|
| DOF | 6 + gripper |
| Motors | Leader: XL330-M077, Follower: XL430-W250 |
| Workspace Radius | ~30cm |
| Material | 3D printed |
| Cost | ~$250 (single arm) |
| LeRobot Integration | Official support |
Suitable for: Entry-level researchers wanting to do real-robot experiments with LeRobot.
Build Notes
- BOM Example (dual-arm system):
| Category | Component | Qty | Unit Price | Subtotal |
|---|---|---|---|---|
| Motor (Follower) | Dynamixel XL430-W250 | 6 | ~$50 | $300 |
| Motor (Leader) | Dynamixel XL330-M077 | 6 | ~$25 | $150 |
| Structural parts | 3D printed parts | — | — | ~$20 |
| Communication | U2D2 USB adapter | 2 | ~$30 | $60 |
| Power | 12V 5A power supply | 2 | ~$15 | $30 |
| Cables | Dynamixel cables | Misc. | — | ~$20 |
| Camera | Logitech C920 | 2 | ~$50 | $100 |
| Total | ~$680 (dual arm) |
SO-100
SO-100 is currently the lowest-cost research-grade robot arm, driven by the HuggingFace community.
| Feature | Specification |
|---|---|
| DOF | 5 + gripper |
| Motors | Feetech STS3215 (bus servo) |
| Control Frequency | 30-50Hz |
| Material | 3D printed |
| Cost | ~$110 (single arm) |
| LeRobot Integration | Official support |
| Communication | Half-duplex UART |
Strengths: Extremely low cost, official LeRobot adaptation, active community.
Weaknesses: Low torque, limited precision, average servo quality.
Build Notes
- Feetech servos use half-duplex UART, requiring a dedicated serial adapter board
- Not compatible with Dynamixel series (different protocols)
- LeRobot provides complete calibration and usage tutorials
- Reference: LeRobot SO-100 Tutorial
Open Manipulator X
An officially produced ROS2-native robot arm by ROBOTIS.
| Feature | Specification |
|---|---|
| DOF | 4 + gripper |
| Motors | 4x Dynamixel XM430-W350 + 1x XM430-W350 |
| Workspace Radius | 38cm |
| Payload | 500g |
| Communication | OpenCR (STM32) + U2D2 |
| ROS2 Support | MoveIt 2 + ros2_control |
| Cost | ~$500 |
Strengths: Best ROS2 integration, has MoveIt 2 configuration, comprehensive official documentation.
Weaknesses: Only 4 DOF, not flexible enough.
Build Notes
- Ready out of the box, no 3D printing needed
- ROBOTIS provides complete ROS2 launch files and MoveIt configuration
- GitHub: https://github.com/ROBOTIS-GIT/open_manipulator
General 3D Printing Recommendations
Most open-source hardware platforms rely on 3D printed structural parts. General recommendations:
| Parameter | Recommended Value |
|---|---|
| Material | PLA+ or PETG (PETG is more durable) |
| Layer height | 0.2mm |
| Infill | 30-50% |
| Wall count | 3-4 |
| Printer | Any FDM (Bambu Lab P1S recommended) |
General Assembly Notes
- Motor ID setup: Each Dynamixel needs a unique ID (use Dynamixel Wizard 2.0)
- Communication baud rate: 1Mbps (1000000) recommended
- Origin calibration: Mark zero positions before assembly
- Cable routing: Prevent cables from being tangled by joints
- Gripper adjustment: Spring pre-tension affects grasp success rate
Quick Selection Guide
| Goal | Recommended Platform | Rationale |
|---|---|---|
| Lowest-cost entry | SO-100 ($110) | Cheapest, LeRobot support |
| LeRobot research | Koch v1.1 ($250) | 6DOF + official support |
| Low-cost teleop device | GELLO ($200) | Adapts to multiple target arms |
| Large-scale data collection | UMI ($200) | Ultra-low cost, platform-agnostic |
| Dual-arm manipulation research | ALOHA ($20K) | Academic standard, original ACT platform |
| Mobile manipulation | Mobile ALOHA ($32K) | Mobile + dual arm |
| Dexterous hand research | LEAP Hand ($2K) | 16DOF, direct drive |
| ROS2 education | Open Manipulator X ($500) | Native ROS2 |
Related Links
GitHub Repositories:
- ALOHA | Mobile ALOHA
- LeRobot (Koch, SO-100 support)
- UMI
- GELLO
- LEAP Hand
- Open Manipulator
Related Notes:
- Teleoperation and Data Collection - Data collection methodologies for each platform
- Dexterous Hands - In-depth discussion of LEAP Hand and other dexterous hands
- Open-Source Frameworks - Software frameworks like LeRobot
- Hardware Selection Guide - Comprehensive selection decision framework