“Our product allows people to function when they otherwise wouldn’t have been able to,” declares Jivak Nischal ’18 of Bottle Sockets, an alternative to costly prosthetics created with fellow Research Science student Jonathan Littmann, Class of 2019. Designed primarily for amputee youth in developing countries—where prosthetics can cost more than six times a family’s yearly income—Bottle Sockets upcycles plastic bottles to serve as sockets for transradial, or below-the-elbow, amputees. Then, custom-designed and 3D-printed attachments—like holders for cups, silverware, or pencils—are secured onto the bottle cap, enabling users to perform different functions.
“The socket refers to the part that attaches to someone’s residual limb,” Jivak explains. “We make the socket by cutting off the bottom of the soda bottle, then heating it around a plaster cast of someone’s residual limb so the bottle takes the shape of the person’s residual limb, forming a tight fit.” In places without resources to create plaster casts, he notes the bottle could be formed directly onto the limb.
Because Bottle Sockets were designed for children—who grow quickly and can need new prosthetics as frequently as every six months—Jivak and Jonathan focused on affordability, but durability was equally important. “Children have a tendency to break things, so making a sturdy prosthetic to endure the behavior of children is going to be a challenge,” they wrote in their proposal.
Finding the Best Bottle for the Task
To identify the strongest bottle for their project, the duo tested three kinds—a standard two-liter bottle, a typical water bottle, and a Gatorade bottle—creating a hook attachment for each one, then hanging a sand-filled bucket on each hook to determine which could hold the most weight. The two-liter and Gatorade bottles were strongest, each able to hold 15-20 pounds; the two-liter bottles were chosen because, Jivak points out, “they are more common and easier to find.”
The students CAD modeled attachments using Fusion 360, and 3D printed them with TPU and PLA plastics. “PLA is a harder plastic that we used for the cup holder, while we used TPU, a softer plastic, for attachments that require items like markers, pencils, or silverware, to be firmly held within the attachment,” says Jivak, adding that each attachment progressed through four or five iterations before he and Jonathan were satisfied with the outcome.
But creating satisfactory attachments was one thing; securing them to a socket proved quite another.
“Sometimes we would screw an attachment to the socket, and it would be facing the wrong way once we’d twisted it all the way,” recalls Jivak. “For example, with something like the pencil holder, the part that holds the pencil could end up facing upwards instead of downwards, which rendered the whole thing useless.”
For most of the year, the partners ignored the problem (“…because we didn’t know how to fix it,” Jivak admits), but they achieved a breakthrough after brainstorming with Mr. Marx and another student.
“We came up with the idea of putting a silicone ring over the threads of the bottle. This meant that the part of our attachment that secures to the bottle didn’t need threads, and could just be a flat cap on the inside, allowing it to grab onto the bottle and adjust the direction of the attachment very easily. This was such a relief because it solved one of our biggest problems and it made our product so much better.”
During Bottle Sockets’ development, Jivak and Jonathan consulted with De La Torre Orthotics and Prosthetics, and Union Orthotics and Prosthetics, to learn how prosthetics are traditionally constructed, “…with Union giving us various models of prosthetics and a plaster cast of someone’s residual limb, so that we could try our prosthetic on something that had the dimensions of a real arm, as opposed to a mannequin arm,” says Jivak.
Bottle Sockets were designed to increase functionality and independence to those in need. But Jivak reveals the project also imparted a powerful lesson to its inventors.
“To be honest, I didn’t really think I was capable of creating something that would work and be able to help people, so I believe this shows what people can do when they put their effort into one thing or a problem that matters to them.”