The world of prosthetics is undergoing a major transformation—but not from a billion-dollar lab or corporate giant. Instead, it’s happening in the basement of a high school in Virginia. Seventeen-year-old Benjamin Choi has developed a brain-controlled prosthetic arm that is affordable, safe, and remarkably intelligent.
Choi’s path to innovation didn’t go as planned. His original idea to study aluminum fuels in a laboratory was canceled due to the pandemic. Rather than giving up, he turned his family’s ping-pong table into a makeshift workshop. As a child, he had been fascinated by a documentary on brain-controlled artificial limbs—technologies that were risky, expensive, and often required surgery. Inspired, he set himself a challenge: could he create a brain-controlled prosthetic arm that was non-invasive and affordable?
The answer is yes. Using a $75 3D printer and common materials like fishing line and rubber bands, Choi built a prototype that reads brain signals via electroencephalography (EEG). Instead of invasive implants, the system uses two small external electrodes—one taped to the earlobe to provide a baseline measurement, and the other on the forehead to capture brainwave signals. These signals are transmitted via Bluetooth to a microchip in the arm, where an artificial intelligence model interprets the user’s intentions into movement.
The ingenuity behind this project is staggering. Choi wrote over 23,000 lines of code and developed seven new sub-algorithms to make the system work, compressing the AI model to fit onto the arm’s microchip. He trained the AI using brainwave readings from six adult volunteers, focusing on specific hand movements. Over time, the system learned to recognize individual neural patterns, becoming more precise with use.
The results are impressive. Choi’s prosthetic achieves a mean accuracy of 95 percent—far above the previous best of 73.8 percent for similar non-invasive devices. It’s strong, made from engineering-grade materials, capable of handling loads of up to four tons, and costs less than $300—compared to the tens or hundreds of thousands typical for commercial prosthetics.
Choi hasn’t gone unnoticed. He was named a top 40 finalist in the Regeneron Science Talent Search and received awards at both the Microsoft Imagine Cup and the Regeneron International Science and Engineering Fair. Yet what inspires him most is the impact on everyday people. Joseph Dunn, an upper-limb amputee, contacted Choi with feedback to make the arm more functional. Collaborations with MIT and Stony Brook University have even brought the design closer to clinical trials.
Choi’s vision extends beyond prosthetic arms. He sees his AI brainwave technology as a way to control wheelchairs, provide communication tools for people with ALS, and power a wide range of assistive devices. With two provisional patents underway, he’s laying the groundwork for a future where these tools are accessible to everyone.
What sets Choi apart is not only his engineering skill but his approach: using advanced technology to create solutions that are affordable and accessible. His story proves that even the most complex problems can be solved with creativity, empathy, and the refusal to accept “there’s only one way to do it.”
Right now, the future of prosthetics is being reshaped in the most unexpected place—a teenager’s basement. Sometimes, all it takes to make technology accessible to everyone is a ping-pong table, a 3D printer, and sheer determination.
