Parents in tow, a ten-year-old boy eagerly guides his wheelchair down Disney World's main drag, taking in the sights. With the iconic Cinderella Castle rising ahead, he pauses before a statue of Mickey Mouse and Walt Disney to rest.
Soon, a real-life Mickey waddles into view, and the boy grins. Using a microphone boom attached to the arm of his chair, he maneuvers his trusty point-and-shoot camera into place and with the click of a remote, captures this moment forever. "That was good," he murmurs. A trip to Disney World is magical for many children. But for this particular boy, there's the promise of extra magic simply in being able to record the experience by framing the shot and clicking away.
This scenario is, at present, only a dream, but thanks to a team of undergraduate engineering students, it could soon be a reality.
The boy (in the interest of privacy, his name has been withheld) has always loved photography, but he has TAR syndrome, a rare genetic disease characterized by an absence of the radius bone in both forearms that leaves his arms much shorter than average. As a result, he has struggled to use a camera. Senior biomedical engineering majors Christal Chow, Alex Li, and Irem Mertol spent last semester designing two custom devices for him: a chair-mounted camera holder that swivels on a boom and a second one that tucks into a support belt, for when he's on foot.
The CamAID project, as the members of the design team call it, was just one of seven carried out by small groups as part of a senior capstone course, "Devices for People with Disabilities," taught by Laurence Bohs Ph.D. '87, an assistant research professor of biomedical engineering.
In Bohs' class, students design and build custom devices that are not available commercially. They work closely with clients identified by Bohs—and often the clients' occupational therapists, physical therapists, and, in the case of children, parents—to tailor their inventions to meet individual needs.
On a Thursday afternoon in early November, Bohs' lab in the Pratt School of Engineering's Fitzpatrick Center is bustling with activity. In one corner, Chow and Mertol are studying a notebook full of diagrams and easurements. Chow holds a camera-size box that they have constructed out of Delrin, a lightweight, durable plastic.
They plan for the camera to sit permanently in this protective case. They are building a high-density polyethylene base that attaches snugly to the arm of their client's wheelchair. The Delrin case, locked onto a tripod, either can be screwed into the base or tucked into the support belt.
Chow takes a green Sharpie and marks the cuts they will make on the case. They will need a hole on one side to accommodate the lever their client will use to turn the camera. They will need another hole on the front for the lens and several more on the back so that the client can see the camera's viewfinder and access the control buttons.
In another corner, senior David Wang is testing a series of electrical circuits. His group's client is a five-year-old girl with Rett syndrome, a neurodevelopmental disorder that has left her with limited motor control. On the suggestion of her therapist, the group is building a device that will catch a ball and allow her to roll it back with the push of a button. Having successfully created a prototype that works using a magnetic coil that cues a lever to tap the ball, Wang is now adding some bells and whistles, lights that flash when the ball enters the box.
Nearby, Matt Angelos, whose team is building a custom lower-body workout device for a twenty-year-old man with cerebral palsy, is putting together a shopping list of the remaining parts his group needs: eight flat-head screws, cap nut, S-hook, L-brackets, I-hook (or is it eye hook? He checks with a group member before adding it). Each group has a $400 budget for supplies, courtesy of a National Science Foundation grant, but many of the things they need can be found right in the lab. The walls are lined with shelves, bins, and cabinets stuffed with screws, bolts, nails, washers, batteries, metal coils, circuit boards, wood, plastic, and sheets of scrap metal—the detritus from more than a decade's worth of projects.
In the early years of the class, Bohs says, he got many of his project ideas from Robin Newton, then head of occupational therapy at the nearby Lennox Baker Children's Hospital. But as word of the program spread throughout the community, he made contacts among other physical therapists, teachers, and clinicians. Many began to approach him with requests of their own. (Five years ago, Richard Goldberg, a professor of medicine at the University of North Carolina at Chapel Hill, and Kevin Caves, a rehabilitation engineer at Duke Medical Center, began team-teaching a spring-semester section of the class in response to client and student demand.)
Many of the devices created in the lab are often surprisingly simple. Take as an example a "shoe helper" that students last year created, allowing a woman with cerebral palsy to cut the time it took to put on her shoes from thirty minutes to less than one. Consisting of only a shoehorn, a hinge, and a heel cup, the device took home a student design award from the annual Rehabilitation Engineering and Assistive Technology Society conference despite, or perhaps because of, its economy. Except in rare cases, Bohs and his students tend to regard electronics and small, delicately crafted parts as malfunctions waiting to happen.
In order to make Bohs' list, project ideas must fit several criteria: useful, but unavailable commercially; novel; complex enough to challenge three seniors for a semester, yet likely to be completed. He gives students a guideline of 200 total hours of work for the typical project, though some take tens, or even hundreds, more.
Once students have identified their projects, they create prototypes based on feedback from clients. Some of the changes that take place after this point are cosmetic. The ball catch-and-return prototype was constructed out of medium-density fiberboard and screws that Wang and his team found lying around the lab. For the final version, they are upgrading to a high-quality Plexiglass that will be laser cut in the Pratt machine shop; then, they will use a solvent to fuse the pieces together seamlessly.
But often the changes are significant. Angelos' group's first prototype for the lower-body workout system was based on a resistance-wheel model, but the client found it too large and bulky. They reviewed several other options, including tension bands and a water-displacement system. For their second prototype, constructed out of wood scraps, PVC pipe, and metal fasteners, they struck on the idea of using a pulley system that would allow the client to lift the weight by pushing down on a pedal.
As they work on their projects, the groups give Bohs regular progress reports. They also meet with their clients periodically and are frequently in e-mail and phone contact with them. "The feedback has been continuous, especially after the prototype presentation," says Ben Wu, who is working with Wang on the ball catch-and-return system. "It's important so that we don't veer off on some tangent where our final product doesn't meet the needs of the client."
At the end of the semester, the groups convene in a small lecture hall in the North Building to present their final projects. Their presentations include project specs, analyses of design and replacement costs, short video clips of satisfied clients, and demonstrations.
One group presents a "mobile cleaning station." The small cart, which features a mini-mop, mini-vacuum, and modified brakes that release only when gripped, doubles as a walker and a cleaning-supply cart for a five-year-old with cerebral palsy who, according to designer Sylvia Qu, likes to "use cleaning as a form of therapeutic strengthening exercise."
A second group shows off a pair of shopping baskets designed to attach to their clients' wheelchairs.
When it's finally the CamAID team's turn, Alex Li is ready. Dressed in a dark suit and gray shirt, he steps to the front of the hall and welcomes his audience.
"For our final demonstration," he tells them, "we decided to take the whole entire class, as well as our client, to the most magical place on Earth: Disney World." A snapshot of the iconic theme park, one that might soon be taken by a young boy in awe, pops onto a projection screen behind him.
Dreams Come True
April 1, 2009