The “Third-Thumb” Invention


The Invention Called The “Third Thumb”

The “Third-Thumb” invention is a prosthetic addition to the digits of your hand. This invention investigates the relationship between the body and prosthetic technology in new ways. “Prosthesis” means “to add, put onto”. The invention is inspired by this word meaning.

How The Third Thumb Works

The dynamic movements of the invention work together to make the thumb more functional as a single finger. The Third Thumb replicates these movements by using two motors pulling against the natural tension of a flexible 3d printed material.

The motors are controlled by two pressure sensors fitted into your shoes. The sensor is located under your toes, and communicate to the thumb via Bluetooth connection. The foot control is inspired by products which require coordination of our hands and feet like driving a car, or using a sewing machine.


Materials Used On The Third Thumb

The base model of the Third Thumb is made of three main 3d printed parts. The cover of the hand and wrist cover for the motors are both 3d printed in rigid, smooth formlabs grey resin. The invention, which is the main part, is live-hinged base design. It is 3d printed out of the tough, 85a, shore flexible filament, Ninjaflex. The parts are connected via a bowden cable system made of teflon tubing and wire.

The Aesthetic Territories Of The Third-Thumb

The project includes two potential aesthetic territories for the Third Thumb. The first is a tool aesthetic. It has an electronic element, a power tool, and a fitness tracker. The second aesthetic territory is a kinetic jewelry Third Thumb. The design is functional and purely aesthetic. The connecting lines on the joints are flexible, which makes the thumb move.

The Third Thumb aims to be challenge the perception of prosthetics. The success of the invention has spread to falcon handlers, jewelry designer, tattoo artists, and others who found good use for the prosthetic thumb.