Processing > Arduino DMX Protocol

Arduino.ino

//DMX communication protocol for Processing ---> Arduino
//Made by Roope Salmi



void setup() {
  Serial.begin(115200);
}

byte message[3];
byte pointer = 0;

void loop() {
  
  
  if(Serial.available() > 0) {
    if(Serial.peek() >= 250) {
      pointer = 0;
      parseMessage(message);
    }
    message[pointer] = Serial.read();
    pointer++;
  }
  
  
}

void parseMessage(byte* mesg) {
  switch(mesg[0]) {
    case 250:
      execute(mesg[1]+1, mesg[2]);
    break;
    case 251:
      execute(mesg[1]+1, mesg[2] + 250);
    break;
    case 252:
      execute(mesg[1]+1 + 250, mesg[2]);
    break;
    case 253:
      execute(mesg[1]+1 + 250, mesg[2] + 250);
    break;
    case 254:
      execute(mesg[1]+1 + 262, mesg[2]);
    break;
    case 255:
      execute(mesg[1]+1 + 262, mesg[2] + 250);
    break;
  }
}

void execute(int channel, int data) {
  Serial.write(channel); //This line of code is unnecessary
  //Now you can do whatever you like with this data
}

Processing.pde

//DMX communication protocol for Processing ---> Arduino
//Made by Roope Salmi


import processing.serial.*;

Serial arduino;

void setup() {
  
  println(Serial.list());
  arduino = new Serial(this, Serial.list()[0], 115200);
  delay(500);
  arduino.write((byte)i);
  
}

void draw() {
  for(int i = 1; i < 60; i++) {
    int data = int(100);
    sendDMXmessage(i, data);
    println(arduino.read());
  }
  
}


//DMX message to arduino:
//ByI|Name   |Description
//1: Header  (message type): >= 250 (in more detail below)
//2: Channel 0-249
//3: Data    0-249
//Don't worry, no data is lost by limiting the values to 249. The header also contains information about both of these values.


void sendDMXmessage(int chan, int val) {
  byte[] message = new byte[3];
  
  if(chan-1 < 250) {
    if(val < 250) {
      //Channel and value below 250
      message[0] = (byte)250;
      message[1] = (byte)(chan-1);
      message[2] = (byte)val;
    } else {
      //Only channel below 250
      message[0] = (byte)251;
      message[1] = (byte)(chan-1);
      message[2] = (byte)(val - 250);
    }
  } else {
    if(chan-1 < 262) {
      if(val < 250) {
        //Channel below 256 and value below 250
        message[0] = (byte)252;
        message[1] = (byte)(chan-1 - 250);
        message[2] = (byte)val;
      } else {
        //Channel below 256 and value above 250
        message[0] = (byte)253;
        message[1] = (byte)(chan-1 - 250);
        message[2] = (byte)(val - 250);
      }
    } else {
      if(val < 250) {
        //Channel above 262 and value below 250
        message[0] = (byte)254;
        message[1] = (byte)(chan-1 - 262);
        message[2] = (byte)val;
      } else {
        //Channel above 262 and value above 250
        message[0] = (byte)255;
        message[1] = (byte)(chan-1 - 262);
        message[2] = (byte)(val - 250);
      }
    }
  }
  arduino.write(message);
}