Karla: A Simple and Affordable 3-D Printed Body-Powered Prosthetic Hand with Versatile Gripping Technology

Abstract

Losing a hand can significantly impact an individual’s physical and emotional well-being. Prosthetic hands can help restore some function and independence for individuals who have lost a hand. However, the prosthetic hands available on the market are prohibitively expensive, especially for developing countries, such as Indonesia. Commercial electronically powered prosthetic hands can be expensive, having prices ranging from $25,000 to $75,000 and annual maintenance costs ranging from $500 to $3000. In contrast, body-powered prosthetic hands are generally cheaper, ranging from $2000 to $10,000, but are still considered expensive for many people in developing countries. To make prosthetic hands more accessible, we have designed a body-powered prosthetic hand, “Karla”, using affordable materials and with as few components as possible. This report presents our proposed designs, the innovations, the parts in detail, and experiences using the designed prosthetic hand. The highlight of our design is a novel whippletree-like mechanism that utilizes the 3-D space to contract the fingers of the prosthetic hand.