New technology enables computing with the wave of a hand


Aoxiang Tang, Liechao Huang and Yingzhe Hu

A FORWARD-THINKING TEAM of electrical engineering students has designed an interactive display surface that allows users to control objects on a screen simply by gesturing in the air. The SpaceTouch surface can either replace an existing touchscreen or be embedded below a table or behind a wall, and can interface with a phone or computer.

A wide variety of uses are possible for the technology, especially in settings where touching a screen is difficult, according to the team, which consists of electrical engineering graduate students Yingzhe Hu, Liechao Huang and Aoxiang Tang.

For instance, a surgeon in an operating room could use SpaceTouch to scroll through a patient’s X-rays. A cook could browse recipes on a surface embedded in an oven or refrigerator door. And three-dimensional sensing could create new possibilities for video games and educational tools.

SpaceTouch will make smartphones, tablets and other computers easier to use in an unobtrusive way, according to Naveen Verma, an associate professor of electrical engineering and a faculty adviser on the project, along with electrical engineering professor Sigurd Wagner and James Sturm, the Stephen R. Forrest Professor in Electrical Engineering and the director of the Princeton Institute for the Science and Technology of Materials.

“We want to interact extensively with our electronics,” Verma said. “But our base technology — the microchip — is small. It’s more appropriate, and I think more compelling, to have a display or interface that is as big as we are.” SpaceTouch makes it possible to control phones or laptops on larger surfaces. Compared to the popular Xbox 360 Kinect gaming console, SpaceTouch can detect motion at shorter distances, in a variety of lighting conditions and using less power.

The 3-D motion sensing of SpaceTouch is made possible by the addition of an extra layer beneath an everyday touchscreen. The upper sensing layer is a matrix of motion-sensing electrodes. A specialized computer chip directs the electrodes to send out a voltage that oscillates, or goes up and down at a constant frequency, creating an electric field that extends to about a foot in front of the screen.

When a hand moves through the electric field, it disrupts the field in a way that changes the frequency of the voltage oscillation. To prevent the display layer from interfering with the motion-sensing electric field, the team added a transparent, conductive shielding layer below the sensing layer, and designed the computer chip to synchronize the voltage oscillations of the two layers.

To explore commercialization of the technology Hu, Huang and Tang participated in the eLab Summer Accelerator Program, which is run by Princeton’s Keller Center in the School of Engineering and Applied Science.

Discovery2014_SpaceTouchdiagram“The eLab program is our first contact with the real business world,” Huang said. “Research is quite different from developing a commercial product.” For example, Huang said, they have learned to consider the needs of different customers and to put together an effective business pitch. The team has obtained a provisional patent, and has already presented SpaceTouch to representatives from large technology companies.

–By Molly Sharlach