17-year-old Benjamin Choi bulit a mind controlling robot arm

When Benjamin Choi was in third grade, he watched a 60 Minutes documentary about a groundbreaking mind-controlled prosthetic arm. The segment showed how researchers implanted sensors into a patient’s brain, allowing her to move a robotic arm using only her thoughts. That moment sparked his fascination with the field, setting the stage for his future interest in innovative prosthetics.

“I was really, really amazed at the time because this technology was so impressive,” he says. “But I was also alarmed that they require this really risky open brain surgery. And they're so inaccessible, costing in the hundreds of thousands of dollars.” After over 75 design iterations, Benjamin Choi has developed a non-invasive, mind-controlled robotic arm made from durable, engineering-grade materials capable of handling weights up to four tons. Powered by an AI-driven algorithm that interprets brain waves, the arm is a breakthrough in affordability, This is a significant reduction compared to existing options:a basic body−powered prosthetic arm costsa round 7,000 dollar, while the advanced Modular Prosthetic Limb, with 26 joints and hundreds of sensors, costs about $500,000 and requires nerve rerouting surgery for thought control and sensory feedback. Choi’s invention offers a more accessible and cost-effective solution for prosthetic technology.

Benjamin Choi developed his AI model by working independently with six adult volunteers, collecting their brain wave data over two-hour sessions at his school and home. Using an electrode on the forehead, he asked participants to focus on clenching and unclenching their hand. He then trained the AI to recognize and interpret these brain signals, creating a system that continuously learns and adapts to the user’s unique brain wave patterns. Over time, the AI becomes more accurate, tailoring its performance to the individual.

Choi’s algorithm, which includes over 23,000 lines of code, 978 pages of math, and seven new sub-algorithms, achieves an impressive 95% accuracy rate—far surpassing the previous benchmark of 73.8% for similar neural networks. Brock Wester, a biomedical engineer at Johns Hopkins University, praised Choi’s work, noting that while the prosthetic arm featured in the 60 Minutes documentary was developed by a large team, Choi accomplished this groundbreaking innovation entirely on his own

Benjamin Choi has earned recognition in prestigious competitions like the Regeneron International Science and Engineering Fair, the Microsoft Imagine Cup, and the National At-Home STEM Competition. In October 2020, he received a manufacturing grant from PolySpectra, Inc., a company specializing in durable 3D-printed materials, to produce his prosthetic arm. Beyond engineering, Choi is a nationally-ranked squash player, student body president, published short story author, award-winning violin soloist, and founder of a school team that competed on NBC’s It’s Academic.

Planning to study engineering in college, Choi aims to refine his prosthetic arm and conduct clinical studies for patients with upper-limb losses. He has secured two provisional patents—one for the neuroprosthesis and another for his brain wave interpretation algorithm. Choi believes his algorithm, which outperforms existing models, has potential applications beyond prosthetics, such as controlling assistive devices like wheelchairs or aiding communication for ALS patients. He sees brain wave interpretation as a rapidly growing field and is optimistic about the broader impact of his work.