How to build PincOpen
1-DoF robot gripper · Beginner
Build Pollen Robotics' Pinc'Open: a 3D-printed parallel-finger gripper derived from Reachy 2, driven by one Feetech STS3215, about €26 in parts.
Mostly printed parts and plug-in servos. Good first build.
Our estimate, part-time
€26.46 for the standalone gripper per the project BOM
CC-BY-SA-4.0
What is PincOpen?
Pinc'Open is Pollen Robotics' budget take on the Pincette gripper on Reachy 2. The machined original costs around €1,700 per unit in small batches; Pinc'Open keeps the two-parallel-finger idea but prints the mechanics and swaps the Dynamixel for a Feetech STS3215.
That servo is the same one used on the SO-ARM100, so the gripper bolts straight onto that arm and its €25-ish price effectively reuses a motor you already own. Fingertips are interchangeable, so you can print a shape for your task.
Pollen is upfront that it won't match an industrial gripper on precision or strength, but the point is to put parallel grasping in reach of anyone with a printer.
PincOpen specifications
- DoF
- 1 (parallel fingers)
- Servo
- Feetech STS3215
- Parts
- 11 unique printed STLs
- Mount
- Standalone or SO-ARM100 interface
- License
- CC BY-SA 4.0
Figures as published by the project. See Sources below.
Bill of materials
| Part | Qty | Notes |
|---|---|---|
| Feetech STS3215 servo | 1 | |
| Servo controller / USB serial board | 1 | Standalone use |
| Printed plates, cam, rods, shells and tips | — | Some parts printed twice |
| 3×16 and 3×24 parallel pins, plain bearings, screws, M3 inserts | — | |
| SO-ARM100 interface or RealSense stand | — | Optional |
Where's the full bill of materials?
The full BOM, with exact quantities and vendors, lives in the project's own files. Prices change often, so treat €26 as a ballpark from the project. Start at the project repository.
Tools you'll need
- FDM printer (PLA)
- Soldering iron for inserts
- Small hex drivers
Step-by-step build overview
Electronics & wiring overview
One servo on the Feetech serial bus. On an SO-ARM100 it simply replaces the stock gripper motor on the arm's chain.
Software
Configuration and control go through Hugging Face LeRobot, the same tooling used for the SO-ARM100.
Tips from the bench
- ☕ Check servo zero before closing up, or the fingers won't meet in the middle.
- ☕ Print a few tip shapes; swapping them is the cheapest upgrade.
PincOpen FAQ
How much does Pinc'Open cost?
About €25–26 in parts, including the STS3215 servo.
Does it fit the SO-ARM100?
Yes, there's a dedicated interface part and it uses the same servo.
Can I sell it?
CC BY-SA 4.0 allows commercial use with attribution and share-alike.
Sources
Written by Bots n' Beans from the project's own documentation. Check the sources for the latest revision before you buy parts.
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