DigiArm: An Anthropomorphic 3D-Printed Prosthetic Hand with Enhanced Dexterity for Typing Tasks
Dean Zadok, Tom Naamani, Yuval Bar-Ratson, Elisha Barash, Oren Salzman, Alon Wolf, Alexander Bronstein, Nili Krausz
AI summary
Problem
Current prosthetic hands lack the precision, affordability, and dexterity required for fine motor tasks like keyboard typing or piano playing, often prioritizing strong grasping over intricate finger control.
Approach
The authors designed DigiArm, an open-source robotic hand featuring independent finger actuation, a manually adjustable finger-spacing mechanism, and a 2D wrist optimized for extended reach, validated through motion-capture-controlled user studies.
Key results
- Open-source, $250 3D-printed prosthetic platform with seven degrees of freedom
- Adjustable finger spacing and 2D wrist mechanism optimized for typing and piano
- User study with 11 participants demonstrating effective real-time key pressing and note playing
- Fingertip force characterization confirming up to 3.6 N output, sufficient for standard keyboards
Why it matters
Democratizes access to dexterous prosthetic control, enabling amputees and researchers to interact with digital devices and musical instruments at a fraction of commercial costs.
Abstract
Despite recent advancements, existing prosthetic limbs are unable to replicate the dexterity and intuitive control of the human hand. Current control systems for prosthetic hands are often limited to grasping, and commercial prosthetic hands lack the precision needed for dexterous manipulation or applications that require fine finger motions. Thus, there is a critical need for accessible and replicable prosthetic designs that enable individuals to interact with electronic devices and perform precise finger pressing, such as keyboard typing or piano playing, while preserving current prosthetic capabilities. This paper presents a low-cost, lightweight, 3D-printed robotic prosthetic hand, specifically engineered for enhanced dexterity with electronic devices such as a computer keyboard or piano, as well as general object manipulation. The robotic hand features a mechanism to adjust finger abduction/adduction spacing, a 2-D wrist with the inclusion of controlled ulnar/radial deviation optimized for typing, and control of independent finger pressing. We conducted a study to demonstrate how participants can use the robotic hand to perform keyboard typing and piano playing in real time, with different levels of finger and wrist motion. This supports the notion that our proposed design can allow for the execution of key typing motions more effectively than before, aiming to enhance the functionality of prosthetic hands.