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SweepSense makes your phone or laptop smarter by using its speaker and microphone

If you’re listening to music or a podcast on your smartphone and need to pause the audio to greet a friend you recognize on the train, you’ll have to remove your earbuds, and then tap the pause button on the phone’s screen. A project called SweepSense removes the need for the second step of that process, and its potential real-world applications are far-reaching.

Three researchers at Carnegie Mellon University are behind SweepSense, which aims to make devices smarter by giving them the ability to sense their surroundings using the speakers and microphones they already have. The project uses a smartphone or laptop’s speaker to send out ultrasonic frequencies, which will reflect off of nearby objects and be measured by the device’s microphone. The information relayed by the reflected sound can be used to trigger specific actions.

SweepSense already has two self-contained demos showing how this can be applied in the real world. In one scenario, a pair of earbuds is plugged into an iPhone. When both earbuds are inserted into the user’s ears, a certain ultrasonic frequency is received by the phone’s microphone. When one of the earbuds is removed, SweepSense makes it possible to determine which earbud was removed.

When an earbud is removed while the user is listening to music, the researchers used software to pause the audio on the device. Alternatively, when an incoming call is received on the phone, the user can simply remove an earbud to answer the call.

The researchers also show how SweepSense can be used on a laptop to determine the angle of the screen. This can be used to trigger certain actions. For instance, if the display is angled back, a MacBook’s dashboard screen will be shown.

SweepSense is far from a perfect approach to making devices smarter. The researchers admit, for example, that the low-frequency ultrasound may be audible to children, the elderly, and animals, which may cause annoyances, according to MIT Technology Review.

The researchers have plans to explore additional applications in public address systems in subway stations and supermarkets, sound systems at concert venues and stadiums, and cars.

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