Amazing Hand is an open-source 8-DOF humanoid hand that packs all its actuators inside the palm — no cables, no deported motors, no forearm clutter. Derived from Pollen Robotics' expertise on Reachy 2, it brings professional-quality dexterity at under 200€.

Four fingers, each with two degrees of freedom (flexion/extension and abduction/adduction), are driven by parallel mechanisms using pairs of Feetech SCS0009 micro servos. The result is a surprisingly expressive hand that can grasp, pinch, point, spread, and form complex gestures.

Key specs:

• DOF: 8 (2 per finger × 4 fingers — index, middle, ring, pinky)
• Mechanism: Parallel mechanism per finger — both joints driven simultaneously by 2 servos
• Servos: 8× Feetech SCS0009 (serial bus, compact)
• Weight: ~400g assembled
• Build cost: Under 200€ (including servos)
• Wrist interface: Designed for Reachy 2's Orbita 3D wrist, adaptable to other platforms
• SO-ARM100 interface: Adapter STL included for mounting on SO-ARM100

Design philosophy: The parallel mechanism is the key innovation: two servos actuate each finger through a gimbal linkage, decoupling flexion/extension from side-to-side movement without requiring tendons or cables. All 8 actuators are housed within the palm housing, keeping the wrist clean and the arm kinematics unaffected.

Control: Two modes: Python serial bus (using a Waveshare SC driver board) or Arduino + Feetech TTL Linker. Both methods and demo code are included in the repository.

An "Amazing Hand Enhanced" branch extends this design with additional capabilities — see the repo for the latest.

Code licensed under Apache 2.0. Mechanical design licensed under CC BY 4.0. Original design by Pollen Robotics — https://github.com/pollen-robotics/AmazingHand

Printing

This is a right hand (the upstream cad/stl folder also ships mirrored L- palm/shell/plate/wrist parts if you want to build a left hand instead — swap the four R- parts below for their L- equivalents).

Finger parts — print 4× each (one set per finger; the four fingers are identical):

• Amazing-Hand-Parts---Distal
• Amazing-Hand-Parts---Distal_Shell
• Amazing-Hand-Parts---Proximal
• Amazing-Hand-Parts---Proximal_Shell
• Amazing-Hand-Parts---Finger_Frame-1
• Amazing-Hand-Parts---Finger_Frame-2
• Amazing-Hand-Parts---Gimbal
• Amazing-Hand-Parts---Link

That is 8 finger STLs × 4 = 32 finger prints. The two shell parts (Distal_Shell, Proximal_Shell) are intended to be printed in flexible filament (Filaflex 82A) for the fingertips/grip surfaces; the frames, gimbal, link, distal and proximal print in rigid PLA.

Palm / wrist — print 1× each (right hand shown):

• Amazing-Hand-Parts---R-Hand_Plate
• Amazing-Hand-Parts---R-Palm_Shell
• Amazing-Hand-Parts---R-Top_Shell
• Amazing-Hand-Parts---R-Wrist_Interface

Linkage / mounting:

• BallJoint_Rod---Spacer — print 1× (linkage spacer)
• SO-ARM_Interface — optional; print 1× only if mounting the hand on a SO-ARM100 arm. The default wrist interface targets Reachy 2's Orbita 3D wrist.

Total in this Print All set: 14 unique STLs, expanding to ~37 physical prints (32 finger + 4 palm/wrist + 1 spacer; SO-ARM adapter optional). Drives 8× Feetech SCS0009 servos (2 per finger). Note: the upstream BallJoint_Rod Length_Toolings part is an assembly jig for cutting the M2 rods to length, not a robot component, so it is excluded here — print it from the source repo only if you need the cutting guide.