SweepSense Pauses Your Music When Earphones are Removed

How many times has this happened to you?

You’re in the groove, listening to that song that gets you in the zone. You’re rocking, and better yet, you’re favorite part is coming up. Just when you’re about to belt you’re favorite line, something rips you from the song, and requires you to pop out your earbuds and divert your attention someplace else. But you forgot to hit pause, and when you finally return, the song is finished.

Well, friend, Carnegie Mellon Univ. researchers have got you covered.

Inspired by the field of soundscape ecology, researchers are working on a new project called SweepSense, which in experiments has effectively been able to pause music when a user removes both earbuds.

“It’s called SweepSense because it sweeps a range of frequencies,” explains Gierad Laput, a developer of SweepSense and a PhD student at Carnegie Mellon’s Human-Computer Interaction Institute, to R&D Magazine.

According to Laput, SweepSense utilizes the speaker and microphone hardware already in place in laptops and smartphones. The SweepSense technology emits an array of inaudible ultrasound sweeps that can be picked up by the speaker system. “Depending on the configuration of the outside environment, the ultrasound that comes back is actually changed,” he said. This allows SweepSense to detect changes in the environment, such as earbuds being plucked out of ears.     

Laput is presenting a paper on the technology this March at the ACM IUI 2016 conference.

In an experiment with 24 participants, the researchers pumped 20 to 22 kHz through the left ear bud and 23 to 25 kHz through the right ear bud. They used “generic, Samsung in-ear headphones.” The microphone, which was 20 cm down the cord, captured the reflected ultrasound. In such a setup, the researchers were able to detect four possible states: both buds in, left bud out, right bud out, and both buds out.

Out of 1,200 classification attempts, the overall accuracy of SweepSense was 94.8%.

An additional experiment carried out by the team used SweepSense to detect the various orientation states of a laptop lid.

While SweepSense utilizes existing hardware, Laput hopes that as hardware improves, they can increase the frequency range of SweepSense to make the ultrasound emitted more inaudible to the human ear. 

Looking forward, he sees a wide range of applications for the technology. For instance, the SweepSense application could be used in cars to detect occupancy, and ascertain whether the doors or  windows are open. This could allow for “richer safety applications.”  

“This approach adds to a growing body of work that can take advantage of devices’ existing speakers and microphones, allowing such techniques to be deployed with a simple software update,” the researchers write in their paper. “In the future, we hope to explore larger contexts that have speakers and microphones, such as public address systems in subway stations and supermarkets, and sound systems at concert venues and stadiums.”