How a 19‑Year‑Old Built a Brain‑Controlled 3D‑Printed Prosthetic Arm

Easton LaChappelle, a 19‑year‑old technical prodigy, gained attention for inventing a prosthetic arm that can be controlled by brain waves.

His motivation began when he met a 7‑year‑old girl named Jenny who was born without arms and whose custom prosthetic cost $80,000, a burden his family could not bear.

At 14, using Lego bricks, fishing line and five independent servers, he built a rudimentary robot arm, which his teacher showcased at a Colorado science fair.

There, he learned of Jenny’s situation and decided to create an affordable, brain‑wave‑controlled prosthetic to help her and others.

Experts dismissed his idea as impossible, especially the brain‑wave control, but a simple game that linked thoughts to a moving ball inspired him to discover a specific correlation between EEG signals and motion, which he applied to the arm.

Over five years, he iterated through countless experiments, designing 3D models, integrating microcontrollers, processors, and motor‑signal conversion, while refining the software based on feedback from many disabled users.

He 3D‑printed all mechanical parts, reducing the arm’s cost to about $500, making it affordable for most families, and the lightweight design proved surprisingly powerful.

Within three months, the final prototype was completed, earning a third‑place prize at the science fair, a second‑place award at an international engineering competition, a personal meeting with President Obama at the White House, and an invitation from NASA to collaborate on projects.

Today, Easton has released the arm’s source code publicly, allowing anyone to download and 3D‑print the prosthetic, encouraging modifications for new applications.

He says, “I hope people can simply use a 3D printer to replicate it, maybe tweak it a bit, and apply it to new uses—just thinking should let the arm perform complex tasks.”