Mobile Computing

Researchers Add Mouse Movement to Phones and MP3 Players

Researchers at Carnegie Mellon University have figured out how to use the same kind of inexpensive optical sensors found in a computer mouse to turn mobile phones and MP3 players into input devices. Nicknamed the "Minput," the technology acts like a mouse or scroll/click wheel, allowing a user to jiggle, twist, or flick the device or scroll it on a surface to activate operations, such as zooming in on an image, turning up volume, or highlighting specific text shown on a screen.

The Minput was developed by Ph.D. student Chris Harrison and professor Scott Hudson through research at the university's Human-Computer Interaction Institute.

"Minput turns out to be a fairly intuitive way to navigate through menus or photo galleries on a device's display without fumbling with tiny buttons or obscuring a small touchscreen with your fingers," said Harrison. "Because we use a pair of sensors, it can respond to a wide range of gestural commands, much like an iPhone or other multi-touch device."

For a prototype, the two researchers mounted two optical sensors on the back of a wristwatch-sized television with a 1.5-inch-diagonal display. Computer processing is performed off-board by a laptop computer. But Harrison said the Minput sensors and processors could be miniaturized to fit inside small mobile devices.

In beta tests, twisting a Minput-equipped prototype device one way or the other allowed the user to perform zooms, and flicking the device against a surface allowed switching between photos or between photo galleries. But Minput also permits high-precision positioning, which is difficult to perform on a small touchscreen, where characters are often far smaller than fingertips.

Should device makers find the Minput a useful addition to their designs, they won't have to invest in creating new sensor technology, Harrison said. "The hard part was done for us; optical sensors are already fantastically well engineered. And at about a dollar apiece, they wouldn't add much to the cost of a mobile phone or music player," he noted. "We just use these sensors in a new and clever way."

Harrison presented a paper on his invention a conference on human factors in computing systems and has posted a video demonstrating the Minput on his Web site.

The work was supported by grants from the National Science Foundation.

About the Author

Dian Schaffhauser is a writer who covers technology and business for a number of publications. Contact her at dian@dischaffhauser.com.

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