PhonePoint App Will Let You Write in Thin Air

Students at Duke University have developed an application that allows users to write short notes in thin air using the accelerometers in their phones.


Consider the following scenario: You’re at the airport, scurrying from parking garage to terminal. Luggage in tow, you glance at the signage as you rush for the elevator: “Level 4, Row C.” Now, rather than juggle your hand luggage, suitcase, PDA, and stylus (or worse, dig for a pen and a slip of paper), you think to yourself: I’ll just remember 4C and write it in my phone when I get inside the airport. Now, when you return to pick up your car next week, you’ll wander around lost like the costars of “Dude, Where’s My Car?”


This scenario, put forth by a group of Duke University engineering students, is a familiar one; people need to jot a quick note or create a small mental cue, but don’t necessarily have time to fish for a pad and pen or pause to tap out a note on their iPhone or Blackberry. As part of a larger effort to explore better uses for the myriad sensors packaged into cell phones and PDAs, these students have developed an application that allows users to write short notes in thin air using the accelerometers in their phones.

Now, after parking your car and before rushing to the eleveator, you simply write the characters “4C” in the empty air in front of you with your phone. Later, checking your email from the tarmac, you see an image message from PhonePoint Pen: “4C,” just as you “wrote” it in the garage.

Accelerometers are the sensors that keep track of the phone’s orientation in space and enable screens to switch from portrait to landscape depending on how the user turns the device. PhonePoint Pen simply translates the user’s gestures into images, allowing the user to write words or create small diagrams.

PhonePoint Pen still has a series of design challenges to overcome before it’s market-ready. Some phones have an accelerometer but not a gyro (which measures rotation rather than the accelerometer’s x-y-z axis directions), so users must keep the device from rotating as they write. Also, the “slate” in the air that users write on has no reference for its position in space, so when creating characters that require users to lift the “pen” from the “paper,” it is difficult for the program to decipher if the stroke is a new character, or if the user is, say, trying to cross a “t.”

But challenges aside, the Duke team is has opened the door to numerous possibilities. The ultimate goal is to create a way to input data into personal devices that doesn’t involve typing on keyboards, which continue to shrink in size as phones become more compact. As the technology develops, they envision writing longer messages and posting information to the Internet faster than ever, without pausing to type anything. One day soon, they suggest, we may be taking our class notes by photographing a slide projected in the classroom and then “PhonePointing” notes onto it, or posting Tweets with the wave of a hand. Makers of paper and pens, take note.

[Duke Engineering Micro-Blog via PhysOrg]