LED strip music visualization using Python and the ESP8266 module.

Demo

Overview

The guide includes everything needed to build an LED strip music visualizer (excluding hardware):

• Python visualization code, which includes code for:
• Recording audio with a microphone (microphone.py)
• Digital signal processing (dsp.py)
• Constructing 1D visualizations (visualization.py)
• Sending pixel information to the ESP8266 over WiFi (led.py)
• Configuration and settings (config.py)
• Arduino firmware for the ESP8266 (ws2812_controller_esp8266.ino)

Computer + ESP8266

To build a visualizer using a computer and ESP8266, you will need: - Computer with Python 2.7 or 3.5 (Anaconda is recommended on Windows) - ESP8266 module with RX1 pin exposed. These modules can be purchased for as little as $5 USD. These modules are known to be compatible, but many others will work too: - NodeMCU v3 - Adafruit HUZZAH - Adafruit Feather HUZZAH - WS2812B LED strip (such as Adafruit Neopixels). These can be purchased for as little as $5-15 USD per meter. - 5V power supply - 3.3V-5V level shifter (optional, must be non-inverting)

Limitations when using a computer + ESP8266: - The communication protocol between the computer and ESP8266 currently supports a maximum of 256 LEDs.

Installation for Computer + ESP8266

Python Dependencies

Visualization code is compatible with Python 2.7 or 3.5. A few Python dependencies must also be installed: - Numpy - Scipy (for digital signal processing) - PyQtGraph (for GUI visualization) - PyAudio (for recording audio with microphone)

On Windows machines, the use of Anaconda is highly recommended. Anaconda simplifies the installation of Python dependencies, which is sometimes difficult on Windows.

Installing python dependencies

The pip package manager can also be used to install the python dependencies.

                                
pip install numpy
pip install scipy
pip install pyqtgraph                      
pip install pipwin
pipwin install pyaudio
                
              

If pip is not found try using python -m pip install instead.

Running the visualization can be done using the command below.

python3 visualization.py /tmp

Arduino dependencies

ESP8266 firmare is uploaded using the Arduino IDE. See this tutorial to setup the Arduino IDE for ESP8266.

Install NeoPixelBus library

Download Here or using library manager, search for "NeoPixelBus".

Hardware Connections

ESP8266

The ESP8266 has hardware support for I²S and this peripheral is used to control the ws2812b LED strip. This significantly improves performance compared to bit-banging the IO pin. Unfortunately, this means that the LED strip must be connected to the RX1 pin, which is not accessible in some ESP8266 modules (such as the ESP-01).

The RX1 pin on the ESP8266 module should be connected to the data input pin of the ws2812b LED strip (often labelled DIN or D0).

For the NodeMCU v3 , the location of the RX1 pin is shown in the images below. Many other modules also expose the RX1 pin.

Setup and Configuration

1. Install Python and Python dependencies
2. Install Arduino IDE and ESP8266 addon
3. Download and extract all of the files in this repository onto your computer
4. Connect the RX1 pin of your ESP8266 module to the data input pin of the ws2812b LED strip. Ensure that your LED strip is properly connected to a 5V power supply and that the ESP8266 and LED strip share a common electrical ground connection.
5. In ws2812_controller.ino:

• Set const char* ssid to your router's SSID
• Set const char* password to your router's password
• Set IPAddress gateway to match your router's gateway
• Set IPAddress ip to the IP address that you would like your ESP8266 to use (your choice)
• Set #define NUM_LEDS to the number of LEDs in your LED strip

6. Upload the ws2812_controller.ino firmware to the ESP8266. Ensure that you have selected the correct ESP8266 board from the boards menu. In the dropdown menu, set CPU Frequency to 160 MHz for optimal performance.
7. In config.py:

• Set N_PIXELS to the number of LEDs in your LED strip (must match NUM_LEDS in ws2812_controller.ino)
• Set UDP_IP to the IP address of your ESP8266 (must match ip in ws2812_controller.ino)
• If needed, set MIC_RATE to your microphone sampling rate in Hz. Most of the time you will not need to change this.