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3D-printed robotic prosthetic wins 2015 UK James Dyson Award

The low-cost prosthetic hand has been awarded top prize in the annual design competition for students.

Dextrus, Open Bionics' 3D-printed robotic hand.Photo by Open Bionics

Low-cost 3D-printed prosthetics, such as the e-Nable open-source prosthetic hand, are doing wonderful things for amputees. Over time, more groups are attempting their own designs, advancing the technology while keeping costs low.

Open Bionics from Bristol, England, and its Dextrus design, originally funded on Indiegogo, is so streamlined it has just won the James Dyson Award in the UK, putting it in the international final for the student design competition.

Compared to other 3D-printed prosthetics available, the Dextrus hand has been designed to look much more like a human hand, with smoothed and rounded contours, and design elements such as knuckles.

But it's what's inside the hand that makes the difference. While many 3D-printed prosthetic hands use myoelectric controls, where a sensor placed on the skin reads the electrical signals sent to the muscles underneath, the most common means of control is a relatively low-tech system of cords that pulls the fingers.

The Open Bionics hand uses a similar system, where steel cables act as tendons that curl the fingers, but these are attached to motors that act as muscles, with each finger individually powered to increase manual dexterity. This gives the wearer a much finer degree of control. The motors can also sense when movement is stopped by an object, which allows a gentle but firm grip.

Because the hand is 3D printed, each one can be modeled specifically for its wearer. The Open Bionics team scans the arm to which the hand is to be fitted and uses that as a basis for the print, scaling the length of the prosthetic as required. The scanning process can be completed within a few minutes.

Once the design is finalised, the hand takes around 40 hours to print. And, moreover, the cost is a fraction of the higher end prosthetics. A finished hand would sell for less than £1,000 (about 1,570 or AU$2,200 converted directly) and it would cost even less if users could make it themselves using the company's open source plans and instructions.

"I was at university studying robotics when I decided to explore the concept of robotic hands further. It was here that I found out that hand amputees have extremely limited access to robotic prosthetics. These tools that could change so many people's lives were prohibitively expensive, around £30,000 to £60,000," CEO and founder of Open Bionics Joel Gibbard explained in the Open Bionics James Dyson Award submission.

"I then found out how crippling these expenses would be for families of young amputees because children need to be refitted once or twice a year as they continue to grow. I convinced my university to allow me to start a project to develop low-cost robotic prosthetics."

So far, the team has worked through 10 working prototypes, refining the design with each generation, and is currently working on an 11th. It plans to start selling the hand in 2016, although currently anyone can use the open-source materials.

Gibbard and Open Bionics will now go on to join the global James Dyson Award, which offers a reward of $45,000 for the winning entry. The international winner will be announced in November.