Sound Direction Detection with ESP32 and Two Microphones

I have just open-sourced my little sound direction detection project here: entron/esp32_sound_direction.

The idea is simple: use an ESP32 and two microphones to estimate where a sound is coming from. We do this naturally with our two ears, and I wanted to see whether I could do the same thing with two microphones.

It is not a lab-grade localization system. It is a practical hobby project that is good enough to explore the basic physics, embedded audio handling, and a few useful signal-processing tricks. If you want to learn these things, I recommend trying it out. It is lots of fun!

At first, I could not make this work and gave up after a few tries. Recently, I asked Codex to examine the reason, and after a few iterations it figured out that I was using two mono channels for the two microphones, which meant the timing was not guaranteed to be synchronized. After switching to stereo, it worked like magic. This is a good lesson that when dealing with sensors, timing synchronization is extremely important.

I also asked Codex to build a web monitor, and after a few tweaks I am quite happy with it: