Jonathan Lalou's blog

In the quest for novel ways to enable communication between web pages running on different machines without relying on a central server, Hubert SABLONNIERE embarked on a truly unique and fascinating experiment: using ultrasonic sound emitted and received through web browsers. This adventurous project leveraged modern web audio capabilities to explore an unconventional method of initiating a peer-to-peer connection, pushing the boundaries of what’s possible with web technologies.

Hubert’s journey began with a seemingly simple question that led down an unexpected path. The idea was to use audible (or in this case, inaudible) sound as a signaling mechanism to bootstrap a WebRTC connection, a technology that allows direct browser-to-browser communication.

Signaling with Ultrasound

The core concept involved using the Web Audio API to generate audio signals at frequencies beyond the range of human hearing – ultrasounds. These signals would carry encoded information, acting as a handshake or discovery mechanism. A web page on one machine would emit these ultrasonic signals through the computer’s speakers, and a web page on another nearby machine would attempt to detect and decode them using the Web Audio API and the computer’s microphone.

Once the two pages successfully exchanged the necessary information via ultrasound (such as network addresses or session descriptions), they could then establish a direct WebRTC connection for more robust and higher-bandwidth communication. Hubert’s experiment demonstrated the technical feasibility of this imaginative approach, turning computers into acoustic modems for web pages.

Experimentation and Learning

Hubert emphasized that the project was primarily an “adventure” and an excellent vehicle for learning, rather than necessarily a production-ready solution. Building this ultrasonic communication system provided invaluable hands-on experience with several cutting-edge web technologies, specifically the Web Audio API for generating and analyzing audio and the WebRTC API for peer-to-peer networking.

Personal projects like this, free from the constraints and requirements of production environments, offer a unique opportunity to explore unconventional ideas and deepen understanding of underlying technologies. Hubert shared that the experiment, developed over several nights, allowed him to rapidly learn and experiment with WebRTC and Web Audio in a practical context. While the real-world applicability of using ultrasound for web page communication might be limited by factors like ambient noise, distance, and device microphone/speaker capabilities, the project served as a powerful illustration of creative problem-solving and the potential for unexpected uses of web APIs. Hubert made the project code available on GitHub, encouraging others to explore this ultrasonic frontier and potentially build upon his adventurous experimentation.

Links:

• Hubert SABLONNIERE’s Twitter
• Hubert SABLONNIERE’s LinkedIn
• Hubert SABLONNIERE’s GitHub
• Video URL: https://www.youtube.com/watch?v=rfEJY7lRrbM

Hashtags: #WebAudio #WebRTC #Ultrasound #Experimentation #JavaScript #HubertSablonniere #DevoxxFR2017