Bionic arms have improved incredibly over the past 10 years. Just yesterday, it was announced that three men had chosen to amputate their arms as a result of nerve damage, and replace them with mind-controlled prosthetics. Researchers have even managed to create devices that allow amputees to feel what they're touching with their new limbs. 

But the only problem with this amazing technology is that it's expensive - prosthetics can cost anywhere from US$20,000 - 100,000, and often it can only be produced by specialists. Which is where this cheap, 3D-printed arm comes in. As Derek Muller from Veritasium shows in the video above, by taking a simple idea and applying the latest in 3D printing, researchers from the University of Central Florida have managed to build a sophisticated bionic arm that costs just $300 to make. And kids absolutely love it.

The device is controlled by three electrodes that attach to the remaining part of the upper arm. When the person wearing the arm contracts their muscles, a little electrical pulse passes through the electrodes and triggers a motor that pulls in the fingers of the prosthetic hand. A second pulse then relaxes the hand.

It's quite a basic action, but as Derek shows, it's pretty easy to control, and children are able to use it to carry books, write and play. And, as one kid says in this video, you can also use it to do somersaults, play video games and hug with two arms. It's the cutest thing we've seen this week.

We also love the little boy at the start, who says he's going to use his "robot arm" to high-five 106 people. And then there's the fact that the kids who receive these 3D-printed arms don't want to blend in - they're actually using their arms to express themselves by designing custom sleeves, say, for example, in a Frozen theme.

There's lots more we can say about this project because it's so cool, but watch the video above to actually see the arm in action, and to find out more about how you can help design and print the prosthetics to help the team achieve their goal of giving free arms to any kid that needs one.

And if you take nothing else from this video, don't forget to be grateful for any fully-functioning arms and high-five someone today.

Source: Veritasium

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