CHESTERFIELD, MO (KTVI) – Sydney Kendall of Chesterfield has a new 3-D robotic arm thanks to some students at Washington University. What started out as a project for a college design class turned the design into reality.
Engineering students, Henry Lather, Kranti Peddada and Kendall Gretsch got an A+ for their project in class, then decided to turn their design into a prosthesis for a patient.
Doctors Charles Goldfarb and Lindley Wall, two hand surgeons at Washington University served as mentors for the project. They also do work at Shriners Hospital for Children and hooked the students up with one of their patients, Sydney. Sydney lost her right hand and part of her arm in a boating accident six years ago. She has two other prostheses that she uses for skiing and biking, but nothing like this.
The students created a computer program containing settings and a code for the 3-D printer. Then, the information was fed into the printer. It used spools of plastic like the kind used in Legos to make Sydney’s new arm. The plastic is heated to melting and the printer starts making the parts. Each part of the robotic hand and arm is made individually. Small parts may take only 20 minutes to make, larger parts over an hour. The entire project took about 13-15 hours.
The brains of the robotic arm were put in place and the parts screwed together. The device is controlled by shoulder movements. The brains include a sensor worn on the shoulder which detects motion. It sends a signal through a cord to a micro controller chip which activates little motors that control the fingers and thumb. It’s all powered by a nine volt battery. The patient, in this case Sydney, can open and close the fingers and the independent thumb by moving her shoulder. Move the shoulder up, the hand opens, move the shoulder down and the hand closes. Move the shoulder forward twice and the thumb opens, move the shoulder back twice and the thumb closes. It allows Sydney to grasp light objects and pick them up.
Sydney says she loves her new 3-D robotic arm because of the movement she can enjoy and thinks it’s cool because in this case, it’s bright pink. She can’t wait for her friends to see it. Her parents, Beth and Mike Kendall were blown away by how the prosthesis functioned and thrilled with the opportunities it presents. The students say they think they can even improve on the robotic arm, possibly adding more function to the thumb and more torque to the fingers so the hand can pick up heavier objects.
It cost about $200 to make the robotic arm with the 3-D printer. This is a lot less compared to a regular prosthesis that can run into the thousands. That’s a major plus according to the senior occupational therapist at Shriners, Valeri Calhoun. She says cost is a big reason why more high-tech prosthetics are not available for children.
For more information: Dr. Charles Goldfarb, Hand Surgeon
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