A South African carpenter who lost four fingers on a circular saw has built his own cut-price prosthetic replacement using 3D printing.
Richard Van As decided to create his own hand after seeing an online video of a mechanical hand made for a theatre production by designer Ivan Owen, in Seattle.
Together they invented Robohand - a device made from cables, screws, 3D printing and thermoplastic. It uses the rotation of a joint to enable five plastic digits to grasp. It looks like a science fiction robot's hand in a science, costs about 500 dollars (£320) to make and can be reproduced using plans on the internet and a 3D printer.
Mr Van As is now on a mission to spread the mechanism across the world. The two gadget-lovers collaborated on developing a design for the device for a wide range of ages that could be used to grab objects, unlike most existing arm prostheses. Mr Van As has fitted Robohands on about 170 people, from toddlers to adults, thanks to donations.
The 3D printer gives much greater flexibility, allowing the device to be re-sized on the computer for each user and then manufactured through the printer. A glove-like covering is fitted in thermoplastic, and then fingers are created on the 3D printer by melting and stacking plastic to make Lego-like digits which are connected to the glove with small cables and screws.
The team got a boost when two printers were donated by the Brooklyn-based Makerbot, one for use in Johannesburg and the other for Seattle.
They then started working on a design to help children with Amniotic Band Syndrome, a condition where children are born without appendages because their circulation is cut off in the womb by amniotic bands.
To spread the device as widely as possible, they made the Robohand an Open Source design available online, and Mr Van As now collects donations to make hands for people around the world.
"I don't want to make money out of misery," he said, dismissing the idea that he could make a profit on the mechanical hand.
Robohands are different from other prostheses for three simple reasons: "functionality, simplicity and cost."
A Robohand is significantly cheaper than the typical 10,000 dollars for a conventional below-the-elbow prosthesis. Eventually Mr Van As would like to see Robohands kits available for sale in shops, so that anyone could simply build one for themselves.
"We took the 3D printing world by surprise," he said. "It wasn't the first medical breakthrough in the 3D world, but people are eager to get a hold of it now."