Intelligent Machines

Cell Phones Make a Touch Surface Smarter

A new system identifies users by their mobile phones.

Tabletop touch screens such as Microsoft’s Surface are designed for sharing and collaboration, but it’s difficult for them to tell one person from another. Researchers in the U.K. have developed a new way to identify different users: via mobile phones.

Touch down: PhoneTouch lets manipulate onscreen photos with their phone.

The prototype system, called PhoneTouch, lets users manipulate onscreen objects, such as photos, or select buttons, by touching any part of their phone to the screen. This also makes it possible to personalize interactions, says Hans Gellersen, a professor of interactive systems at the University of Lancaster, who developed the system with his student Dominik Schmidt.

PhoneTouch also makes it possible to transfer files between the phone and the surface. “Surfaces in general are good for working together in parallel,” says Gellersen. “But when people work together they also want to bring information into the group.”

PhoneTouch uses a camera positioned beneath the surface to recognize finger contact. The system can also discern the pattern made when the edge of a phone touches the surface. “The phone gives a different visual blob than the finger,” says Gellersen.

To identify which phone is in contact with the surface, the PhoneTouch interrogates the accelerometers built into connected phones to see which of them experienced a slight bump at precisely the moment of contact. “These two events are correlated in time,” he says. This is an approach known as separate event detection.

“It’s very clever,” says Eva Hornecker, who studies the usability of touch surfaces at Strathclyde University. “Normally surfaces don’t know who’s who.” PhoneTouch could, perhaps, ensure that files taken from a phone can be shared with others, but without allowing anyone else to alter or save them, Hornecker notes.

Separate event detection is already used by the popular smart phone app Bump, which lets users exchange information by shaking, or “bumping,” two phones close together. PhoneTouch differs in that it allows the pairing of a personal device with a shared device, says Gellersen. “PhoneTouch not only establishes a connection but allows the Phone to be used as a stylus on the surface, to select specific widgets.”

Schmidt says that there is a slim chance that the system will be confused when two phones touch it simultaneously. But a user study has shown that it identifies the correct device 99.99 of the time. The researchers will present the work at the User Interface Software and Technology symposium in New York this week.

“It’s a great idea,” says Rob Miller, head of the User Interface Design Group at MIT. “The traditional desktop approach of username and password entry doesn’t make much sense on a multitouch tabletop,” because text entry is less natural.

Mitsubishi Electric has demonstrated a touch surface called DiamondTouch that uses sensors in chairs to match touches to different people. But using a phone may be more convenient. “Mobile phones are already ubiquitous–people carry them anyway.” Miller agrees. “Phones are very personal. We almost always have them with us.”

Tech Obsessive?
Become an Insider to get the story behind the story — and before anyone else.
Subscribe today

Uh oh–you've read all five of your free articles for this month.

Insider Premium

$179.95/yr US PRICE

More from Intelligent Machines

Artificial intelligence and robots are transforming how we work and live.

Want more award-winning journalism? Subscribe to Insider Premium.

  • Insider Premium {! insider.prices.premium !}*

    {! insider.display.menuOptionsLabel !}

    Our award winning magazine, unlimited access to our story archive, special discounts to MIT Technology Review Events, and exclusive content.

    See details+

    What's Included

    Bimonthly home delivery and unlimited 24/7 access to MIT Technology Review’s website.

    The Download. Our daily newsletter of what's important in technology and innovation.

    Access to the Magazine archive. Over 24,000 articles going back to 1899 at your fingertips.

    Special Discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

    First Look. Exclusive early access to stories.

    Insider Conversations. Join in and ask questions as our editors talk to innovators from around the world.

You've read of free articles this month.