PincOpen Gripper

PincOpen is a low-cost (~25€) open-source parallel-finger gripper derived from Pollen Robotics' Reachy 2 "Pincette" gripper — bringing professional-grade gripper design to the DIY robotics community at 1/70th of the original cost.

The gripper uses a cam-driven parallel jaw mechanism: a single STS3215 servo drives both fingers simultaneously through a cam plate, keeping both jaws parallel throughout the full range of motion. This is the same servo used in the SO-ARM100, so if you're already building that arm, you already have the hardware you need.

Key specs:

• Cost: ~25€ total (including motor already in SO-ARM100 BOM)
• Motor: 1× Feetech STS3215 serial bus servo
• Mechanism: Cam-driven parallel jaw — both fingers stay parallel through full stroke
• Mounting: SO-ARM100 compatible interface plate included
• Tips: Interchangeable! Standard rubber tips, camera mount, and custom tip support included
• Print time: ~3–4 hours total (PLA or PETG recommended)

Interchangeable tips: PincOpen features a modular tip system. The standard release includes flat rubber tips for general grasping, a camera mount for wrist-eye setups, and a blank tip template for custom applications. TPU tips can be printed directly onto the tip support for soft-grasp applications.

Torque limiting: The cam geometry provides a natural soft stop — the motor position target is set just past full close, and the mechanical cam prevents over-torque from snapping the jaws. This is a clever mechanical substitute for the torque-limiting mode found on expensive Dynamixel servos.

The gripper is fully compatible with the SO-ARM100 arm via the included Interface_ARM100 adapter plate, and all 14 structural components are 3D-printable.

Hardware and design licensed under CC BY-SA 4.0. Original design by Pollen Robotics — https://github.com/pollen-robotics/PincOpen

Printing

Print files match the upstream source (github.com/pollen-robotics/PincOpen, cad/stl/) one-to-one — all 14 parts are byte-identical to the repo. Print one of each (PLA or PETG, ~3–4 h total).

Core gripper (print 1 each):

• Bottom_Plate.stl, Top_Plate.stl — main body plates
• Interface_ARM100.stl — SO-ARM100 mounting adapter
• Motor_Flange.stl — STS3215 servo flange
• Cam.stl — cam plate that drives both jaws in parallel
• Driving_Rod.stl, Distal_Rod.stl, External_Rod.stl, Internal_Rod.stl — linkage rods
• Distal_Shell.stl — finger shell
• Tip_Support.stl — tip carrier
• Removable_Tip.stl — standard grasping tip

Optional camera mount (wrist-eye setups):

• Camera_basement.stl, Camera_mobile_sup.stl — mounts for an Intel RealSense D405 (camera itself is optional per the BOM; skip these two if you don't need vision).

Tips are modular: the standard Removable_Tip works for general grasping; for soft-grasp you can re-print the tip in TPU directly onto Tip_Support. The BOM lists 2 removable tips so you can keep a spare or a second material on hand.

Motor & fasteners: 1 × Feetech STS3215 serial-bus servo plus the screws/inserts/bearings listed in the BOM — sourced, not printed.

Cleanup note: The list previously held 42 files — each of the 14 parts was triplicated (a clean-named copy plus an orobot-upload-<uuid> copy and an orobot-dl-<timestamp> copy from re-imports). The 28 byte-identical duplicates were removed, leaving exactly one clean copy of each part.