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Multi-Touch Screen Helps the Disabled

Assistive Device Built By Engineering Student

UMass Lowell student demonstrates self-built multi-touch screen
Electrical and computer engineering senior Xiangwei Zhuo demonstrates his self-built multi-touch screen.

By Edwin L. Aguirre

An engineering student has created an interactive multi-touch screen to assist people with physical disabilities.

Xiangwei Zhuo, an electrical engineering senior, built the device to help those with motor or cognitive challenges overcome their limitations.

“With this device, they can point to and touch the screen instead of using a conventional mouse or keyboard,” says Zhuo. “This will enable them to browse the web, write e-mail, manipulate photos or play games and music much more easily.”

Last December, Zhuo delivered his device to a Bridgewell facility in Lynn that offers services to people with physical and developmental disabilities.

“The project is beyond what any of us could have imagined,” says Patti Peterson, an occupational therapy consultant for Bridgewell. “The number of people who will benefit from Xiangwei’s work encompasses so many more individuals than we had expected. He spent time working with us to make sure that we knew exactly how the system works. Our clients here are already enjoying the device.”

Real-World Solutions to Real-World Problems

Zhuo’s project is part of the College of Engineering’s Assistive Technology Program. Founded by Prof. Donn Clark in 1991, the program provides service-learning experience to students, requiring them to adapt existing technology or design new devices to meet the specific needs of the disabled client. Parts are paid for by a grant from the National Science Foundation. Students supply the labor, and the resulting projects are delivered to clients free of charge.

“Our students talk with the clients, interact with them and are motivated by them,” says Alan Rux, the program’s technical director. “Students have already developed at no cost to the clients a number of devices that improve the quality of life for the disabled.”

Zhuo decided to build the device after reading a do-it-yourself article in

“Since I knew how to build a computer, I was interested to see if I can build a Windows-based multi-touch screen interface at relatively low cost,” he says.

Zhuo’s tabletop screen consists of a 24-by-32-inch transparent acrylic sheet lined with vellum that has been coated with silicone rubber. Rows of infrared (IR) light-emitting diodes (LEDs) along the edges of the acrylic illuminate the inside of the acrylic. When one or more fingers are pressed against the acrylic, some of the IR light are reflected down, where they are detected by an IR webcam below as bright spots on the screen. From that image, software running in an adjacent computer tracks the fingers’ location and movement and uses that data to control multi-touch applications. The computer’s desktop and virtual keyboard are displayed on the screen’s underside using a DLP projector, and the entire unit is encased in a nice wooden cabinet.

“Since the screen is multi-touch, the user can use all 10 fingers simultaneously,” he says. “Or there can be more than one user at the same time.”

The device works similarly to Microsoft Surface, an interactive surface computer with a tabletop 30-inch touch-sensitive flat-screen display used mainly for entertainment, gaming and product demos. It lets users grab and manipulate digital content and move information using simple touch and hand gestures and object recognition instead of a typical mouse and keyboard.

Microsoft Surface costs up to $12,000 apiece, while Zhuo built his device for less than $700.

“This includes the cost of the DLP projector,” he says. “The only component not included in the price tag is the PC.”

Making a Difference in People’s Lives

Peterson says UMass Lowell’s Assistive Technology Program never ceases to amaze her and the Bridgewell staff.

“The quality of students and their ability to understand our thoughts and dreams, to make them a reality, continues to impress us and really makes a difference in our ability to service a very special population,” she says.

For more information, visit the Assistive Technology Program website.

The multi-touch screen can respond to up to 10 points of contact simultaneously, compared to only one or two fingers as with a typical touch screen.
Zhuo poses with John Crowley, a client at the Bridgewell facility in Lynn.