MP3R

I2S is one of those protocols that looks narrow until you understand what it actually enables. Audio is the obvious application; but the same interface drives accelerometers, microphones and multi-sensor streaming arrangements that come up constantly in serious embedded work. We wanted to know it properly.

The MP3 player was the vehicle because it's a genuinely complete problem; power constraints, real-time data throughput, a user who notices immediately if something is wrong. It also had to be small enough to take on a run without thinking about it, which ruled out anything half-finished.

The result is a fully working player on a custom PCB. The I2S knowledge it produced is what actually carries forward into client work; sensor fusion, audio capture, anything that moves data at that layer. The player just happens to be the most enjoyable way we've found to demonstrate it.