Wednesday, April 01, 2009

A Better, Cheaper Multitouch Interface

Multitouch displays getting more usable ...

"Over the past few years, the world has fallen in love with multitouch displays. But today's consumer interfaces have some drawbacks: touch screens such as those on the iPhone and Plastic Logic's upcoming e-reader only work with a finger, not a stylus or even a gloved hand. Other displays, such as Microsoft's Surface and Perceptive Pixel's wall-sized screens, are rigid, relatively expensive, and currently fairly bulky.

New research from New York University, however, promises to make multitouch interfaces that are cheap and flexible and can be used by fingers and objects alike. The technology, called Inexpensive Multi-Touch Pressure Acquisition Devices (IMPAD), can be made paper thin, can easily scale down to fit on small portable devices, or can scale up to cover an entire table or wall. The researchers will present IMPAD next week at the Computer Human Interaction conference in Boston.

The iPhone captures information about touch by measuring a change in capacitance when a finger or other conducting object comes in contact with the display. Surface screens use cameras to see the position of objects on the tabletop. Perceptive Pixel's displays also use cameras, but in a different way. Those cameras are used to track infrared light as it scatters in the presence of a finger or stylus. While Perceptive Pixel's touch screens collect pressure information, it's still impractical to use cameras for smaller or touch interfaces. IMPAD takes a different approach by measuring a change in electrical resistance when a person or object applies different pressure to a specially designed pad, consisting of only a few layers of materials.

"One of the problems that's been endemic to multitouch sensors is . . . you're either touching it or not touching it," explains Ken Perlin, a professor of media research at NYU. "A significant amount of potentially useful information is thrown away because the sensor isn't capturing the subtleties." But with a pressure-sensitive touch pad, a device can see how hard a person presses, opening up another dimension of the user interface. The researchers have shown that their pressure-sensitive touch pad can be used for virtual sculpting and painting applications and for a simulated mouse with left clicks, right clicks, and drags, as well as for musical instruments like a piano keyboard. (See video.)

The hardware that composes the demonstrated prototype is relatively straightforward, explains Ilya Rosenberg, a graduate researcher and lead author on the IMPAD paper. It consists of two plastic sheets, about 8 inches by 10 inches, each with parallel lines of electrodes, spaced a quarter inch apart. The sheets are arranged so that the electrodes cross, creating a grid; each intersection is essentially a pressure sensor. Crucially, both sheets are covered with a layer of force sensitive resistor (FSR) ink, a type of ink that has microscopic bumps on its surface. When something coated in the ink is pressed, the bumps move together and touch, conducting electricity. "The harder you press, the more it conducts," says Rosenberg."    (Continued via Technology Review, Kate Greene)    [Usability Resources]

Pressure Pad - Usability, User Interface Design

Pressure Pad


Blogger Kirsten said...

Thank you for sharing this article! I find the new technology coming out for touchscreens is rather interesting! I am currently taking a graduate class on Human Computer Interaction at University of North Texas. I have been studying the use of touch screens in the iPhone and other devices like Kindle. After purchasing an iPod Touch a few months ago, I was really bummed that a stylus pen could not be used on the system. Sometimes it is hard to touch small areas of the screen with my finger and a stylus pen would be more accurate since the tip of the pen is so small.

Like it was mentioned in the article, you are either touching the screen or not. There is no inbetween. I am excited about the new Force Resistance Sensor technology! The possibilities seem endless now that pressure can be measured. This new technology will add so many more opportunities for newer ways to use touch screens on future touch devices!

12:34 PM  

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