Using Artnet DMX and the ESP32 to Drive Pixels

Contributors: Englandsaurus

Creating an ArtNet Node on the ESP32

We now have to get our ESP32 to listen for DMX data on the WiFi network. In order to do this, we'll first need to setup the ESP32 Core on the Arduino IDE. In order to do this, head over to that section of the ESP32 Hookup Guide.

Once we have this set up we'll need to download the ArtNet WiFi library along with a branch of the FastLED library that plays nicely with the ESP32. These libraries are downloadable below.

Once we have our libraries installed, load the following example code (which was adapted from the ArtNet Neopixel example contained within the library) into your ESP32. Explanations for subroutines are found within the comment of the code.

language:c
#include <WiFi.h>
#include <WiFiUdp.h>
#include <ArtnetWifi.h>
#include <FastLED.h>

//Wifi settings - be sure to replace these with the WiFi network that your computer is connected to

const char* ssid = "SSID";
const char* password = "pAsSwOrD";

// LED Strip
const int numLeds = 120; // Change if your setup has more or less LED's
const int numberOfChannels = numLeds * 3; // Total number of DMX channels you want to receive (1 led = 3 channels)
#define DATA_PIN 12 //The data pin that the WS2812 strips are connected to.
CRGB leds[numLeds];

// Artnet settings
ArtnetWifi artnet;
const int startUniverse = 0;

bool sendFrame = 1;
int previousDataLength = 0;

// connect to wifi – returns true if successful or false if not
boolean ConnectWifi(void)
{
  boolean state = true;
  int i = 0;

  WiFi.begin(ssid, password);
  Serial.println("");
  Serial.println("Connecting to WiFi");

  // Wait for connection
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
    if (i > 20){
      state = false;
      break;
    }
    i++;
  }
  if (state){
    Serial.println("");
    Serial.print("Connected to ");
    Serial.println(ssid);
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println("");
    Serial.println("Connection failed.");
  }

  return state;
}

void onDmxFrame(uint16_t universe, uint16_t length, uint8_t sequence, uint8_t* data)
{
  sendFrame = 1;
  // set brightness of the whole strip 
  if (universe == 15)
  {
    FastLED.setBrightness(data[0]);
  }
  // read universe and put into the right part of the display buffer
  for (int i = 0; i < length / 3; i++)
  {
    int led = i + (universe - startUniverse) * (previousDataLength / 3);
    if (led < numLeds)
    {
      leds[led] = CRGB(data[i * 3], data[i * 3 + 1], data[i * 3 + 2]);
    }
  }
  previousDataLength = length;     
  FastLED.show();
}

void setup()
{
  Serial.begin(115200);
  ConnectWifi();
  artnet.begin();
  FastLED.addLeds<WS2812, DATA_PIN, GRB>(leds, numLeds);

  // onDmxFrame will execute every time a packet is received by the ESP32
  artnet.setArtDmxCallback(onDmxFrame);
}

void loop()
{
  // we call the read function inside the loop
  artnet.read();
}

With this code loaded into the ESP32, go ahead and open your serial monitor to 115200 baud and check that the ESP32 is connecting to WiFi. Once it is, make note of the IP address shown in the Serial monitor.