Students Create Proximity Sensor System for Wheelchair-Bound Woman

A team of first-year engineering students at Elizabethtown College have created a proximity sensor system that will help a disabled woman better maneuver her power wheelchair.

The Audible Warning Sonic Sensor System, which is mounted to and powered by Melissa Sneath’s wheelchair, produces a warning sound when she is approaching an object or wall. The sound changes as she gets closer to the object, allowing her to correct her course and avoid a collision.

“As a result of her cerebral palsy, Melissa has perceptual issues,” said Carol Sneath, Melissa’s mother. “She knows how to maneuver her chair, but she has issues with her distance from objects. This is a big deal, because it makes her dependent on others for direction.”

Sneath proposed the project last year to Elizabethtown physics professor Troy McBride. His “Introduction to Engineering” students design and construct community service projects each year to reinforce some of the core elements of the course, such as teamwork, problem solving, design, and application of basic engineering principles.

Sneath learned about the students’ efforts through her work at Lancaster’s United Disabilities Services. She turned to McBride after searching unsuccessfully for a commercial sensor system to help her daughter. “There is a similar device in Europe, but because of patent issues, it hasn’t been able to be purchased by any U.S. vendors,” she said.

The difficulty of the project discouraged McBride’s students last year, and none chose to undertake it. “The proximity sensor project struck me as an excellent project for computer engineering students, but I was aware that the technical challenge may have been daunting to first-year students,” McBride said.

This year’s class, however, produced a team of students — Pat Gianelli of Ephrata, Matt Lauver of McAlisterville, Paul Stegner of East Berlin and Christopher Yorgey of Allentown — who were up to the challenge.

“What made us step up? It was a combination of the challenge of the project and the opportunity to do a lot of good,” said Yorgey. He and Gianelli also share an interest in electronics and thought they would enjoy working on the sensor system.
The team visited Sneath’s house in Lancaster “to get a feel for the environment,” according to Yorgey. They measured the width of doorways and hallways and took reference photos to be used later. Gianelli then designed and built the power circuit and processor, to which four sensors were attached – two for the front of the chair and two for the sides.

The sensors, which are mounted in cases, can be programmed to trigger at specific distances. “We don’t want the system to trigger too much so that it becomes annoying,” Yorgey said. A detachable speaker mounted on Melissa’s headrest allows her to easily hear the signals sent by the sensors. “We can also customize the sounds so that the system uses those that Melissa likes,” Yorgey added.

Both Sneath and McBride are pleased with the team’s work. “I was very impressed with the responsibility, work ethic, project management and technical ability of this team of four students,” McBride said. “They met every deadline, had the initiative to consult with senior computer engineering students and professors for technical suggestions, and designed, purchased components, constructed and programmed the entire product.”

“Melissa very much enjoyed having these young men around her,” Sneath said, “and I am very excited about this device, because I believe it will have a huge impact on her life.”

At Elizabethtown College — central Pennsylvania’s premier small, comprehensive college — 1800 men and women enjoy personal attention, breadth of curriculum, experiential learning and a commitment to serving others. Elizabethtown has been ranked for 11 consecutive years by U.S. News and World Report as one of the top comprehensive colleges in the North.