Building a Reactive Audio Visualizer

Processing, streaming, and visualizing sounds on some hardware I put together

Being able to host a dance party in my apartment might be a thing of a past, more collegiate era. I nonetheless embarked on this project to engineer the ultimate rave-style light show beneath the occasional footsteps of my unknowing landlords. There were ultimately more hours sunk into this than I would like to admit and this work is still very much in a project state, but I am quite proud of what I was able to get out of my hobby coding ambitions on this one.

To start off, what exactly did I build here and isn't it just those cheap, blinding LED strips that can be found hanging around the average male college dorm room? The short answer is yes, I build a controller to create visuals on an addressable LED strip. The longer answer is that I created extensible software to be transform system audio into a byte protocol that can be streamed wirelessly to this network-enabled red flag [1].

Esp LED Driver

The simplest part of this system is the LED driver, which takes a dumb-simple packet format that I came up with and reads a UDP stream containing nothing but 4-byte chunks in the following format:

    struct packet_bytes {
        char led_index;
        char r_led;
        char g_led;
        char b_led;
    };

    union packet_union {
        packet_bytes packet_rep;
        int int_rep;
    };

As I said earlier, this runs on an Esp8266 (actually an esp-01 that I had laying around from ) I decided some time ago that systems was the lowest level I could go while still maintaining my sanity writing code, so I ended up using the Esp8266 and NeoPixel libraries to do the heavy lifting with networking, addressing the LED strip, and whatever ESP wrangling needs to be done. The arduino sketch for this was thankfully incredibly small and is probably not going to see many code changes going forward