I've been experimenting with ultrasonic data transmission in the context of ultrasonic payments. This repository contains a small demo sending a Stripe Payment Link between a merchant's transmitter device (e.g. tablet) and a customer's receiver (e.g. mobile phone).
It is relying on quiet.js and sends data via inaudible sounds.
If you want to try it out, play around with the live demo, and if you want to learn more, check out the blog post.
If you want to run this locally, start by cloning this repository, and start a Python server with:
# Using Python 2
python -m SimpleHTTPServer 3000
# Using Python 3
python -m http.server 3000