When you learned about the Doppler Effect in high school physics class—the wave frequency shift that occurs when the source of the wave is moving, easily illustrated by a passing ambulance—you probably didn't envision it helping control your computer one day. But that's exactly what a group of researchers are doing at Microsoft Research, the software giant's Redmond, Washington-based lab. Gesture control is becoming increasingly common and is even built into some TVs. While other motion-sensing technologies such as Microsoft's own Kinect device use cameras to sense and interpret movement and gestures, SoundWave does this using only sound—thanks to the Doppler Effect, some clever software, and the built-in speakers and microphone on a laptop.
Researchers at Microsoft Research, mention that the technology can already be used to sense a number of simple gestures, and with smart phones and laptops starting to include multiple speakers and microphones, the technology could become even more sensitive. The idea for SoundWave emerged last summer, when researchers were working on a project that involved the use of ultrasonic transducers to create haptic effects, and they noticed a sound wave changing in a surprising way as he moved his body around. The transducers were emitting an ultrasonic sound wave that was bouncing off researchers' bodies, and their movements changed the tone of the sound that was picked up, and the sound wave they viewed on the back end.
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