background:
I am working on an interactive installation featuring a lighting chandelier made up of lots of addressable RGB light sources.  I am using Processing to generate the colour behaviours and colour maps that will be displayed across the light fitting -- this is clearly where Processing really demonstrates its power!  

proposal - DMX output module:
The lighting chandlier is controllable via industry-standard DMX lighting protocol.  At present, I will be using a seperate VIDEO to DMX converter software to get the Processing output displayed on the light.   What would be great is if I could have Processing directly generate the DMX commands.   It would be an interesting Library to have as it would allow Processing to interface with an enormous library of lighting / special effects / controllers, etc..
In my immediate application, it seems that grabbing RGB values from the Processing screen and output these as RGB values over DMX should not be too difficult?
This however is a little beyond my own programming abilities and therefore I would really like to hear what you think about this, and if anyone else is interested in collaboration, or even already developing something similar?

notes:  
about DMX:   http://en.wikipedia.org/wiki/DMX_(lighting)

generating the commands through processing shouldn't be too bad, though is there a good way to get an interface to it? either via serial or network? from the wikipedia page, it's talking about it being an XLR cable that's sending RS-485, so you'll need another hardware layer between p5, so it all depends on what that layer looks like--for instance, if there's a converter box that hooks up to your serial port or something like that. and sends out the signals over XLR or whatever.

VVVV has DMX output as well. There's lots of discussion on it over. at their tiki, including practical tips, info about hardware interfaces etc.

I just got one of those enttec USB pro DMX controllers (not the openDMX model though).

It's fairly easy to interface with it via the serial library.  I've borrowed a DMX dimmer pack and am having WAY too much fun with some desk lamps now.

There's a message format you have to use to communicate with the DMX controller over USB (as a virtual com port).  You can find the spec for talking to the DMX box on the enttec site.  This sketch will fade channel zero depending on the mouse position.  The DMX pro has several messages to do things like set the DMX timings etc, but right now I've only implemented the "send DMX packet" message..

Hope this helps someone.  Depending on how much work it turns out to be, I may build a library around this thing.

-Ben

Code:

import processing.serial.*;

static byte DMX_PRO_MESSAGE_START = byte(0x7E);
static byte DMX_PRO_MESSAGE_END = byte(0xE7);
static byte DMX_PRO_SEND_PACKET = byte(6);

Serial dmx;
int universeSize = 6;// lower = faster updates.. 
byte[] channelValues;

void setup()
{
  size(256, 200);
  frameRate(60);
  
  channelValues = new byte[universeSize];

  for(int i = 0; i < universeSize; i++)
  {
    channelValues[i] = byte(0);
  }

  dmx = new Serial(this, "COM8", 115200);
}

void draw()
{
  setDMXChannel(0, mouseX);
}


int getDMXChannel(int channel)
{
  return int(channelValues[channel]);
}

void setDMXChannel(int channel, int value)
{
  if(channelValues[channel] != byte(value))
  {
    channelValues[channel] = byte(value);
    byte[] data = new byte[universeSize+1];

    data[0] = 0; // DMX command byte..

    for(int i = 0; i < universeSize; i++)
    {
	data[i+1] = channelValues[i];
    }
    
    dmxMessage( DMX_PRO_SEND_PACKET, data );
  }
}

void dmxMessage( byte messageType, byte[] data )
{
  byte[] message;
  int dataSize = data.length;
  message = new byte[5 + dataSize];
  
  message[0] = DMX_PRO_MESSAGE_START;
  
  message[1] = messageType;
  
  message[2] = byte(dataSize & 255);
  message[3] = byte((dataSize >> 8) & 255);
  
  // there's probably a faster way to do this...
  for(int i = 0; i < dataSize; i++)
  {
    message[i+4] = data[i];  
  }
  
  message[4 + dataSize] = DMX_PRO_MESSAGE_END;

  dmx.write(message);
}
 

Hi,

I just finished a project for a class at the university:

http://users.design.ucla.edu/~acolubri/home/Group/PopMotion/PopMotion.html

where I used a DMX board and a DMX USB pro adapter.

Based on the code posted here I implemented a little DMX object for processing. It's simpler than the original example, and I think it's a little bit faster too:

http://users.design.ucla.edu/~acolubri/home/Group/PopMotion/code/DMX.pde

Andres

i meant with an Enttec DMX USB Pro

Since i am on an Mac (OS X 10.5) the port ist cu.usbserial-ENR2OIA8 and tty.usbserial-ENR2OIA8 but usually its the cu.usbserial-ENR2OIA8.

and the error only occurs, as soon i enter a value greater then 0 for the value of the channel:
dmx.setDMXChannel(1,0);  <- no error, but nothing happens
dmx.setDMXChannel(1,2); <- error

best

Yes i chekc it all, when i am using vvvv.org it works perfectly, i only get this java.lang.NullPointerException in processing. maybe trouble with the port, i tried several