Here is a neat technology that provides you with an acoustically-driven method to interact with your smartphone. Acoustruments are passive, powerless mechanisms made from plastic that let you get a more interactive experience while using your smartphone. The idea was inspired by wind instruments. One end of the instrument attaches to the microphone while the other connects to the speaker.
As you can see in the above video, such a technology can be used to develop smart cases, toys, and even interactive dolls. Yet another fascinating idea from DisneyResearchHub.