Subway napping is an enjoyable but risky pastime: Fall asleep too deeply and you could miss your stop and wind up late for your meeting/movie/wedding. Some have slept so long that they awoke in an outer-borough neighborhood they had never even heard of before and were never seen again.
This was the problem confronting Tobi Domhan in May. An exchange student from Stuttgart, Germany, who took an internship with Bitly after finishing his studies at UMass Amherst, Domhan had been in New York City for about two weeks when his girlfriend fell asleep on the subway and "ended up where she didn't plan to go," he says. That's when Domhan had an idea.
"In the previous semester I had done some work on activity recognition using the accelerometer in smartphones," the 25-year-old, now back in Germany working on his master's in computer science, tells Daily Intelligencer. "The task was to distinguish walking from other daily activities, like going up and down the stairs. This got me thinking: Why couldn't I detect whether the train is moving or not through the accelerometer of the phone? While GPS is not an option underground, this could work, I thought."
A few months later, the MetroNap App was born. The app can tell how many stops have passed based on the motion of the train and will wake you from your slumber at the stop of your choice. For now, it's only available for Android phones, so iPhone users will just have to continue sleeping in two-minute increments.