Show HN: ggwave – tiny data-over-sound library

Hi HN, this is a small C++ library for data-over-sound communication. It utilizes a very simple FSK modulation approach for audible and ultrasound transmissions, aiming to achieve reliable data transfer over reasonable distances.

To showcase the library, I also implemented a free mobile app called "Waver: Data Over Sound" which you can easily install and try out (iOS and Android). The app uses "ggwave" and allows you to send and receive text messages using the phone's speakers and microphone. There is also an option for file sharing where 2 or more devices connect with each other by emitting sounds and transmitting files peer-to-peer without any global server.

Here is a quick video demonstrating it's functionality: https://www.youtube.com/watch?v=Zcgf77T71QM

Would love to hear what you think about this project and more importantly - what could be some interesting applications for this type of communication.