Devlog #1 — Cable-Actuated Anthropomorphic Robotic Hand

Date: June 26, 2026
Project: Servo-driven, tendon-actuated robotic hand → future prosthesis R&D

Overview

Kicking off the build log for this one. The long-term goal is a functional prosthetic hand, but right now the focus is proving out the core actuation mechanism: an anthropomorphic hand where the fingers are driven by cables (tendons) rather than having a motor sitting in each joint.
Current State of the Build

Two digits are up and mounted on the wrist and fore arm assembly:

Each finger is a multi-joint, 3D-printed linkagecurrently being actuated and tested independently of a full hand.
Actuation is cable-driven through the clear tubes running down each finger, they’re tendon sheaths. They let a servo mounted remotely (down at the base) pull a cable up into the digit via a pully without the servo’s weight or footprint being in the finger it self. The Servos are wired to a PCA9685 16 channel servo driver and an Arduino Nano for easy wiring , code organization, and power distribution as the 22 servos can realistically draw up to 8 amps from my power supply.

Engineering Notes

The cable-actuation choice is the most important design decision so far. Trade-offs worth tracking as the project matures:

Pros: lighter digits, smaller joint profile, mimics natural tendon-driven motion, easier to pack more DOF into a small finger footprint.
Cons to watch: cable stretch/friction inside the tubing over many cycles, routing complexity as digit count goes up, and the need for some kind of tensioning adjustment per tendon.

Next Steps

Finish the remaining three fingers
Design a palm assembly that properly houses tendon routing and pulley/anchor points
Investigate feedback — flex sensors or load cells on the tendons for grip force sensing
Start scoping the eventual socket/interface and control input