Mini-Arm
A miniature 3D-printed robot arm with a gripper, with STL and SolidWorks files provided for building it.
Project documentation
Before you build
Five answers, each linked to its source
What does it cost?
About $82Basic build
The total cost summary lists the Basic Build at about $82. bom.rst
Can I sell what I build?
YesCommercial use OK
Hardware MPL-2.0 · Software Mozilla Public License 2.0. Licensing source
What’s open?
5 of 6CAD: AvailableBOM: AvailablePCB: Not documentedCode: AvailableSim: AvailableGuide: Available
PCB not documented. All six files
What does it run on?
Simulation: ROS2 description includes URDF and meshes. Software
Is it maintained?
Active
Latest activity Oct 23, 2026 · 23 commits in the last 52 weeks · 1 contributors Activity
01 / Under the shell
The specifications.
Hardware, build and software on one sheet. Every fact links to where we found it.
Mini-Arm is a miniature robot arm with a gripper and 3D-printable components. The repository provides STL and SolidWorks files, a bill of materials, assembly instructions, and CircuitPython firmware for Raspberry Pi Pico 2.
Hardware
- Actuators
- 7 · Micro servos: six joints and gripper wiring.rst
- Build
- 3D-printed · PLA/PETG · FDM Documentation
- Degrees of freedom
- 6DOF README
- Weight
- Less than 1 lb (~0.3 kg) README
Building it
Software & simulation
02 / The files behind the robot
What’s open.
Six parts of the build, each checked separately. Gaps stay visible.
| Part | Status | What’s there | License | Source |
|---|---|---|---|---|
| CAD | Available | SolidWorks CAD source files are provided. | Not documented | solidworks/ |
| Bill of materials | Available | Bill of materials spreadsheet. | Not documented | bom.xlsx |
| Electronics | Not documented | Not documented | Not documented | No source found |
| Code | Available | CircuitPython firmware for Pico and Pico 2. | Not documented | circuitpython/ |
| Simulation model | Available | ROS2 description includes URDF and meshes. | Not documented | miniarm_description/ |
| Assembly guide | Available | Assembly guide with step-by-step build instructions. | Not documented | assembly.rst |
03 / Know before you build
Can you sell it?
YesCommercial use OK
The whole repository, design files included, is MPL-2.0. You can build, modify and sell robots based on it, as long as you keep the license and copyright notices.
- Hardware
- MPL-2.0
- Software
- Mozilla Public License 2.0
04 / The upstream project
Is it maintained?
ActiveLatest activity Oct 23, 2026, 7 days before the snapshot
- Stars
- 14
- Forks
- 2
- Contributors
- 1
- Latest release
- v1.0.0 · Nov 4, 2023
Snapshot captured Oct 30, 2026. Recorded figures, not live metrics. Active: activity within 90 days of the snapshot. Quiet: within a year. Dormant: longer.
05 / Parts & kits
A head start.
Maker-listed sellers only. No affiliate links or paid placement.
Kit availability is not documented in our reviewed sources.
06 / Side by side
Compare with other arms.
The three arms with the closest documented maker’s cost. Same sources, same rules.
| Robot | Cost | Open files | Can I sell it? | Runs on | Maintained | Stars |
|---|---|---|---|---|---|---|
| Mini-ArmThis robotJonathan Shulgach | About $82Basic build | 5 of 6 | YesHW MPL-2.0 · SW Mozilla Public License 2.0 | ROS 2Raspberry PiPython | ActiveOct 23, 2026 | 14 |
| SO-101TheRobotStudio × Hugging Face | $121.94per follower arm | 5 of 6 | YesHW Apache-2.0 · SW Apache-2.0 | LeRobotMuJoCo | ActiveOct 6, 2026 | 7,831 |
| AM-ARM200Li Yiteng and Wu Zhiyong | $243.33follower arm BOM | 4 of 6 | YesHW Apache-2.0 · SW Apache-2.0 | LeRobot | QuietJun 18, 2026 | 90 |
| PingTi Armnomorewzx | About $261single PingTi arm | 4 of 6 | YesHW Apache-2.0 · SW Apache-2.0 | LeRobot | ActiveOct 20, 2026 | 55 |
| This robotMini-Arm | SO-101 | AM-ARM200 |
|---|---|---|
| Cost | ||
| About $82 | $121.94 | $243.33 |
| Can I sell it? | ||
| Yes | Yes | Yes |
| Open files | ||
| 5 of 6 | 5 of 6 | 4 of 6 |
| Runs on | ||
| ROS 2, Raspberry Pi, Python | LeRobot, MuJoCo | LeRobot |
| Maintained | ||
| ActiveOct 23, 2026 | ActiveOct 6, 2026 | QuietJun 18, 2026 |
Upkeep is measured against each robot’s own snapshot. Costs keep the maker’s scope, so check what each figure covers.
See them in the table07 / Follow the evidence
Open books.
Repository files are pinned to commit 6555026. Websites and papers are listed with their review dates.
- 01README.md at 6555026Reviewed Oct 30, 2026
- 02LICENSE at 6555026Reviewed Oct 30, 2026
- 03docs/source/hardware/assembly.rst at 6555026Reviewed Oct 30, 2026
- 04docs/source/hardware/bom.rst at 6555026Reviewed Oct 30, 2026
- 05docs/source/hardware/wiring.rst at 6555026Reviewed Oct 30, 2026