During the pandemic, 17-year-old teen Benjamin Choi used his time to design a device that may remove the need for brain surgery in people with amputations.
10 years ago, when Choi was in third grade, he watched a documentary on 60 Minutes about prostheses controlled by the mind.
The researchers placed tiny sensors into the motor cortex part of a patient’s brain and she was able to move the robotic arm using her thoughts.
This fascinated Choi and reminded him of something out of a Star Wars movie.
He found this tech to be impressive; however, he soon realized that this possibility demands a risky open brain surgery. And, these aren’t easily accessible options since they may cost hundreds or thousands of dollars.
Years Later, Choi Designs a Less Invasive Prosthetic Arm on His Own
Years after this moment, when the pandemic started in 2020, Choi, a tenth grader at the time in Virginia, had some free time so he decided to dedicate it to inventions.
Unfortunately, the labs where he planned to spend his summer and research aluminum fuels had closed. This is when he thought of the documentary he watched years back and started to work on designing a prosthetic arm that will be less invasive than other options.
For this to happen, he created a makeshift lab on his ping-pong table in the basement. Sometimes, he would work there for 16 or more hours. He designed the first version of the arm with the help of his sister’s $75 3D printer and some fishing line.
The printer was unable to make pieces bigger than 4.7 inches in length so Choi had to print the arm in smaller pieces and then rubber banded and bolted everything together. He needed some 30 hours for this part.
The first version worked with brain wave data and head gestures and Choi was kind enough to share the instructions online so that others who want can also build their own. Choi had some experience in building robots and coding from his participation in competitive robotics at elementary, middle, and high school levels.
He has also attended world championships several times. In ninth grade, he began learning computer programming languages python and C++ through videos on Stack Overflow, a website that programmers use.
The Robotic Arm: After 75 Changes in Design, Looks Like this
After making more than 75 adjustments to the robotic arm’s design, the non-invasive and mind-controlled device is made from engineering-grade materials that can withstand weights of up to four tons.
The arm works using an algorithm driven by AI which interprets the brain waves of the user. The production costs are around $300 which is much less than the current options on the market since a more basic and body-powered prosthesis for upper limbs requires spending around $7000.
As of 2015, the advanced and full-arm Modular Prosthetic Limb with 26 joints, hundreds of sensors, and curling up to 45 pounds costs a staggering $500,000!
Combined with surgery for nerve rerouting that will control the arm, this prosthesis gives patients a chance to control the limb through their thoughts and even experience texture through it.
Choi’s robotic arm design uses EEG to avoid the invasive techs of other prostheses. These devices record the electrical activity of the brain with sensors put on the head. These are often applied in medicine for epilepsy or other disorders of the brain.
Choi’s system uses two electrodes. One is a baseline sensor clipped on the earlobe and the other is on the forehead and gathers EEG data. The electrode on the forehead collects brain wave info that is sent to a microchip in the prosthetic arm through Bluetooth.
The AI deciphers the data and transforms it into predictions of what the brain’s thinking. The arm is also moving through head gestures and stops using intentional blinks.
His design caught Joseph Dunn’s attention. This person is an upper-limb amputee from Pennsylvania and they started talking remotely.
Choi said how it helped him immensely to work with Mr. Dunn. It was inspiring and motivating. Though it may sound cliche to some, helping people through engineering and tech is possible, said Choi.
A Finalist in the Regeneron Science Talent Search
The robotic arm invention earned the 17-year-old senior at Potomac School a place in the top 40 finalists in one of the oldest and most prestigious competitions in math and science for high school seniors.
The first place was reserved for Christine Ye from Sammamish who made a new way to analyze gravitational waves released from collisions between neutron stars. Choi says that this means so much and that he appreciates that his work is recognized and is so grateful.
To make the model, he had to work with six adult volunteers and collected their brain wave data, both at school and at home.
The algorithm has more than 23,000 code lines and 978 pages of math and seven entirely new sub-algorithms.
Such inventions, like Choi’s, are pivotal since estimates show that around 2 million individuals live without a limb in the US and around 185,000 amputations happen yearly.
The WHO notes that one in ten individuals who need assistive products like orthoses and prostheses has access to them due to the high cost, low awareness, and lack of availability, finances, policies, and trained personnel.
Choi was chosen last summer to be a Simons Fellow at Stone Brook University.
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