attachable 3D-printed robot thumb grasps objects like a real finger

3D-printed ‘Third Thumb’ on human augmentation

Wearing an extra finger helps people in different ways. It can replace a missing part of the hand, provide extra support for holding objects, and open ways for further research on the future of human body-part augmentation. This very last statement has propelled neuroscientist Tamar Makin and designer Dani Clode of Cambridge University to investigate the impending body motor augmentation using advanced technologies, potentially using 3D printers to create the devices and robotic limbs.

On March 3rd, 2023, Makin moderated the talk on the future of motor augmentation for the body at the American Association for the Advancement of Science (AAAS). ‘With direct brain-machine interfaces, patients are already able to control bionic arms by the power of their thought, bypassing an injured spinal cord or a missing limb. Now, beyond restoration of lost function, there is a growing interest in exploiting similar technologies for human motor augmentation,’ the talk description states.

images courtesy of Dani Clode

Robot limbs that use pressure

Before the presentation, Dani Clode had already designed the Third Thumb, ahead of her collaboration with Tamar Makin and their team in The Plasticity Lab at University College London and Cambridge University. The 3D-printed, robotic thumb was part of Clode’s Masters at the Royal College of Art for which she won multiple awards. It offers extended help to its user and explores the relationship their body has with augmentative and prosthetic technology. The prosthetic finger moves as the user controls press their toes on the floor.

Users first wear the motor-connected finger device around their wrists. Through the microcontroller attached to their arm, the users wirelessly connect it with the robotic finger and the pressure sensors found under the big toes. These interconnected systems allow the thumb to move and work on its own based on the users’ control of their toes. In a way, the 3D-printed finger can read the users’ desired action through pressure.

Clode says that the Third Thumb instigates a necessary conversation about the definition of ‘ability’. ‘The origin of the word ‘prosthesis’ meant ’to add, put onto’; so not to fix or replace, but to extend. The project is inspired by this word origin, exploring human augmentation and aiming to reframe prosthetics as extensions of the body,’ she says.

the robot finger can hold objects

Advancing body augmentative research

Clode and Makin inquire on how can the brain adapt to augmentation by adopting the properties of neuroplasticity into the equation, seeing what resources the brain uses to control a body part that has never been there before, and investigating how it can be harnessed to improve usability and control of future prosthetic and augmentative devices.

In an article in The Guardian regarding human augmentation, Clode discloses the recent research she and the researchers conducted at the Royal Society summer science exhibition where the participants had the opportunity to try out the extra thumb. She says that out of 600 people, 98 percent of them could use the robotics, 3D-printed finger within a minute, meaning the participants could already make the handy finger function to their needs.

the 3d-printed robot finger is triggered using sensored systems

As the research team further delves into human augmentation, neuroscience questions arise that help them and the viewers ponder the breakthrough 3D-printed, robotic prosthetics can provide. ‘What physiological and cognitive resources could be harnessed to use a body part that humans haven’t evolved to control?’

These were some of the questions that Makin addressed during her recent session at AAAS. The talk’s description lays out that ‘designers will likely need to draw novel approaches from outside the assistive technology toolbox in order to control these new body parts in collaboration with existing biological limbs.’