Overview

Track Visualizer provides the ability to control Wu281x addressable RGB LEDs via a web server hosted on a Raspberry Pi. A variety of light effects can be selected from the web page. Additionally, there is integration with Spotify's API to enable synchronizing the light effects with the playing track.

IMG_1419.mp4

Installation and Running

Acknowledgements

This project very much depends on ExpressJS(https://expressjs.com) and the RPi WS281x Python bindings.

Instructions

You must have relatively recent versions of python3, node, and npm installed on the Raspberry Pi. If running Raspbian, sudo apt update && sudo apt install python3 nodejs should be sufficient to get you going.

First, clone the repository.

git clone https://github.com/mfinnessey/track-visualizer

Next, install the necessary node and pythondependencies.

sudo pip install rpi_ws281x
cd track-visualizer
cd express
npm install

Finally, launch the light control script and web server (note that both must be running at the same time - for testing this is most easily done from separate shells, but in the long run I would recommend using something like screen or tmux).

sudo node app.js
sudo ../lights.py

If you want to take advantage of the integration with Spotify's API, then modify the client_id, client_secret, and redirect_uri to the values provided by Spotify and the URI of the Raspberry Pi on your local network (probably http://raspberrypi.lan or http://raspberrypi.local depending on your router's manufacturer). Note that you will have to restart the web server and light control script for this to take effect.

Architecture

The Raspberry Pi hosts a web server running on ExpressJS, a NodeJS derivative. The web server accepts user requests for light patterns which it then relays to the Python script that controls the LEDs via a named pipe. This sometimes requires the web server to make requests to Spotify's API as well. The light control script is composed of two threads - one for processing the incoming IPC messages and another for actually controlling the lights. The multithreading is perhaps a bit gratuitous considering the GIL, but there's always PEP 703 to get ready for :)