Student-Created App Smartly Locks and Unlocks Phone

Have you ever listened to a six-minute-long voicemail of muffled background noise? You were most likely the victim of a pocket dial, an accidental call from a phone placed in a pocket or handbag. It can be embarrassing and a waste of precious cell phone data and minutes.

William Xiao, a sophomore in the McCormick School of Engineering, has created an Android app that will make pocket dials a thing of the past. Named Pocket Lock, the application locks the phone when you put it in your pocket and unlocks it when you take it out. It can also lock the phone when the phone is held upside down or placed face down on a table. Users can then unlock the phone by simply turning it over, turning it right side up, or waving their hands over it. (A passcode-protected phone, after unlocked, still requires a passcode.)

“It’s just more convenient,” said Xiao. “It’s hard to think that pressing the ‘on’ button is inconvenient, but once you start using the app, you’ll never look back.”

A computer science major, Xiao began building the app last winter with self-taught skills learned from an online ebook. His app takes advantage of two sensors inherent in smartphone hardware—the accelerometer, which senses the angle at which the phone is held, and the proximity sensor, which senses when something, such as a waving hand, is nearby.

Since becoming available in August, Pocket Lock has been downloaded more than 55,000 times, and the numbers grow everyday. Xiao said the fast success is due to positive reviews from technology websites Gizmodo, Digital Spy, and Lifehacker.

“I check Lifehacker everyday to learn about new apps,” Xiao said. “When I saw my own app on the site, I almost had a heart attack. After that article, Pocket Lock was downloaded 7,000 times in one day.”

Xiao is working on more functions for the application, including a power-saving nighttime mode that automatically unlocks and locks the phone depending on the time of day. In the meantime, the app is currently free to download from the Google Play Store.

“Pocket Lock actually works exactly as advertised, with no fuss,” said the Lifehacker review. “That’s what makes it such a cool app to have.”