In an effort to bring more functionality and interactivity to a device that is often just a large monolithic touchscreen, researchers at Carnegie Mellon University and Disney Research have come up with a series of accessories that manipulate sound coming from a smartphone's speaker to serve as an external controller.
Called Acoustruments, the cheap plastic accessories direct an ultrasonic sound from a smartphone's speaker back to its own microphone. But in-between the speaker and mic are obstacles that change or vary the pitch and intensity of the sound — similar to how moving the slide on a slide whistle can change the sound it produces.
An accompanying app knows exactly what sound is being produced, and by comparing that to what the microphone ends up hearing, the Acoustrement can determine how a user is interacting with the device. The accessory could be as simple as a button that serves as a snooze button, or a wheel that changes settings like a dial, or a full-on smartphone case that knows when the device is sitting on a table, being held, or even squeezed like a camera.
And because it doesn't actually draw any power from the device (besides the constant ultrasonic tone being produced) this added functionality doesn't hinder a smartphone's already limited battery life. So eventually it could be implemented directly into a device's housing, adding more buttons or ways to interact with a smartphone, without any negative consequences. [Disney Research]