The field of prosthetics is experiencing a quiet revolution, and it’s not being spearheaded by a giant research facility or a billion-dollar corporation. It’s happening out of the basement of a Virginia high school student. 17-year-old Benjamin Choi has developed a mind-controlled prosthetic arm that’s inexpensive, non-surgical, and artificially intelligent.
His adventure started when the pandemic derailed his initial plan to study aluminum fuels in a lab. Rather than shelve his dreams, he converted his family’s ping-pong table into a workshop. As a child, Choi had watched a documentary about mind-controlled prosthetics—limbs that demanded perilous brain surgery and were expensive. That lingered with him. Years later, he made a challenge to himself: could he create a prosthetic arm that you could control with your mind, without having surgery, and one that anyone could buy?
It turns out the answer is yes. With a $75 3D printer and common materials such as fishing line and rubber bands, Choi created a prototype that reads brain signals through electroencephalography (EEG). Rather than having anything implanted into the brain, the system involves two tiny external electrodes-one taped to the earlobe to provide a baseline measurement, and the other on the forehead to capture brainwave information. That is transmitted wirelessly through Bluetooth to a microchip within the arm, where an artificial intelligence model interprets the user’s intentions into motion.
The degree of innovation here is astonishing. Choi wrote over 23,000 lines of code and created seven new sub-algorithms to get it to function, shrinking the entire AI model so that it would fit onto the chip within the arm. He trained the system using brainwave readings from six adult volunteers, having them concentrate on particular hand movements. The AI became better with time, learning to identify individuals’ unique neural patterns and adjust accordingly, becoming more precise the more it was utilized.
The results speak for themselves. Choi’s prosthetic achieves a mean accuracy of 95 percent—well above the previous best of 73.8 percent for similar non-invasive devices. The arm is strong, built from engineering-grade materials, and can handle loads of up to four tons. Even more impressive, it costs less than $300 to make—compared to the tens or hundreds of thousands for most commercial prosthetics.
His work hasn’t gone unnoticed. Choi was named a top 40 finalist in the Regeneron Science Talent Search and won awards at the Microsoft Imagine Cup and the Regeneron International Science and Engineering Fair. But what excites him most is the impact on real people. Joseph Dunn, an upper-limb amputee, reached out after learning about Choi’s project and provided feedback that helped make the arm more practical. Collaborations with MIT and Stony Brook University have brought the design closer to clinical trials.
Choi’s ambitions go far beyond prosthetic arms. He believes his AI brainwave technology could be used to control wheelchairs, help people with ALS communicate, and power a range of assistive devices. With two provisional patents already filed, he’s laying the groundwork for a future where these tools are widely available.
What stands out about Choi’s story isn’t just the technical brilliance—it’s his philosophy. He’s showing that cutting-edge technology doesn’t have to be expensive or exclusive. With creativity, empathy, and a refusal to accept “that’s just how it’s done,” even the hardest engineering challenges can be reimagined.
Currently, the future of prosthetics is taking shape in a most improbable location—a teenager’s basement workshop. And sometimes a ping-pong table, a 3D printer, and sheer determination are all it takes to make technology accessible to all.
