A 14-year-old in a Colorado farm town built a robotic hand from LEGO bricks, fishing line and surgical tubing, then met a 7-year-old at a science fair wearing an $80,000 prosthetic arm she had already outgrown — his next version, 3D-printed, came in under $400, and NASA took him on as an intern at 17

Easton LaChappelle grew up in Mancos, Colorado — population about 1,200, tucked in the state’s remote southwest corner near the Four Corners. There was, by his own account, very little for a teenager to do. So at 14, bored and curious, he decided to build a robotic hand.

He knew nothing about electronics or programming when he started. He taught himself both, from YouTube videos and by messaging experts around the world, and built the thing out of what was lying around the house.

A hand made of toys

The first version was almost comically improvised — and it worked.

The fingers were surgical tubing. The tendons were fishing line. The frame was LEGO bricks, and five hobby servos gave each finger its own motion, driven by a microcontroller and a glove he wore to puppet it. Later versions doubled down on the scavenging: dental rubber bands from someone’s braces sprang the fingers back, a windshield-wiper motor became an elbow, a Nintendo Power Glove became the controller.

The hand could grip a soda can, shake your hand, toss a ball. In 2011, as a high-school freshman, LaChappelle took it to the Colorado State Science and Engineering Fair and won third place in the senior engineering division.

Third place turned out to be the least important thing that happened there.

The girl with the $80,000 arm

At the fair, LaChappelle met a seven-year-old girl who had been born without her right arm. She was wearing a prosthetic — one of the most advanced models available at the time — and in the course of talking to her, he learned two facts that redirected his life.

The first was the price: the arm had cost $80,000. The second was worse. She would outgrow it, the way a child outgrows shoes, and her family would have to buy another — and prosthetics for growing kids mean paying that kind of money again and again as the body changes. For all that money, the arm did startlingly little.

That was, in his words, the “ah-ha moment.” A soda-can-gripping LEGO hand was a clever toy. An $80,000 device a child would outgrow was a problem worth solving. He set out to build a real prosthetic — one that did far more, for a tiny fraction of the cost.

From $80,000 to a few hundred

The lever that made it possible was 3D printing, which LaChappelle taught himself next — eventually building his own 3D printer to learn how to “think in 3D.”

Where the $80,000 arm was expensively machined and rigid, LaChappelle’s design was printed in plastic from open-source files anyone could download and improve. His second version grew from a hand into a full arm; the third added a wireless headset that read the user’s brainwaves, letting a wearer move the limb by concentrating. The whole thing ran on an Arduino microcontroller and hobby-grade parts.

The cost figures reported for his prototypes cluster in the few-hundred-dollar range — often cited at around $250, with the arm he built for the girl who inspired it put at roughly $400. Against $80,000, the exact figure almost doesn’t matter. He had cut the price of an advanced prosthetic by more than 99 percent, and made the design free for anyone to build on.

The handshake and the internship

The work pulled LaChappelle into rooms most teenagers never see. He carried a version to the White House Science Fair and shook President Obama’s hand with his robotic one — the president reportedly suggesting he show the technology to DARPA. He took second place at the Intel International Science and Engineering Fair, the country’s top pre-college competition.

And in 2013, at 17, he was brought on as an intern at NASA’s Johnson Space Center in Houston, working on Robonaut 2 — the agency’s humanoid robot — helping refine the finger and hand designs meant to work in space. The kid who’d built a hand out of LEGO because he was bored was now building hands for a robot destined for orbit.

He did not stop there. LaChappelle founded a company, Unlimited Tomorrow, to drive the idea to its conclusion: custom, low-cost prosthetics made by 3D-scanning an amputee’s residual limb, generating a tailored design automatically, and printing it — so that a child in a remote town could get a fitted, advanced arm without the $80,000 and without the trip to a specialist.

The engine underneath the whole story is a single comparison a fourteen-year-old could see and the prosthetics industry had somehow priced past. One arm cost $80,000 and a child would outgrow it. Another could be printed for a few hundred dollars and updated as fast as the child changed. LaChappelle didn’t invent the robotic hand, or 3D printing, or brainwave control. He noticed that a seven-year-old was wearing a fortune she’d grow out of by Christmas — and decided the fortune was the bug, not the price of admission.