Linux ArtNet Node

Written by Thomas Hinterberger and Simon Newton.

This HOWTO outlines a method for creating an ArtNetNode on an Intel/AMD32 Computer (minmum proved: PI/200 32 MB Ram/400MB Harddisk ) using an Enttec Open DMX USB Interface (not the Pro). For instructions on how to install on to a USB stick see http://d-i.pascal.at/

This howto uses the Debian Sarge Netinstall-CD-Image (100 Mb) - http://www.debian.org/releases/sarge/debian-installer/

The computer must be connected to the Internet to download the packages. Its easiest if you have a DHCP server on your network (most routers come with this feature).

Prerequisites: None. It helps if you know Linux a bit and have installed Debian before, but there is plenty of other documentation for that.

Initial Debian Install

For installation follow: http://www.howtoforge.com/perfect_setup_debian_sarge (enter linux26 at the boot prompt to install a 2.6 kernel)

Enter something useful for the hostname like "node1", you can leave the domain name blank.

Set up a user other than root on the machine.

On page 2 of the above guide, for the screen "Debian Software Configuration" , don't check any boxes. We'll install the other packages later.

On the Configuration Exim v4 you choose "No configuration at this time".

After the install completes it will present you with a login prompt. It's now time to install the ArtNet software and DMX driver.

Installation of Lighting Software

Log in with the user name and password you set up previously.

now you type to the console with the following convention:

1. command Type command as root- to get root type 'su' followed by the root password

$ command Type command as user - to get user type exit

Edit the /etc/apt/sources.list file, you'll need to be root to do this:

$ su
# nano /etc/apt/sources.list

Add add the following line:

deb http://www.nomis52.net/data/debian ./

If you used nano to edit, you can save the file with ctrl o + enter . Then exit nano with ctrl x.

Update the package lists and install the required software:

# apt-get update
# apt-get install kernel-headers-$(uname -r) g++ make libartnet1 artnet-examples

Make a note of the version of your kernel-headers that are going to be installed.

Exit the root account, and download and compile the dmx_usb driver:

# exit
$ git clone git://github.com/lowlander/dmx_usb_module.git
$ cd dmx_usb_module
$ make
$ cd ..

Now we need to install the kernel module. Adjust these lines for your system using the version of kernel headers that were installed.

$ su
# cp dmx_usb_module/dmx_usb.ko /lib/modules/2.6.X-Y-386/kernel/drivers/usb/serial/dmx_usb.ko
# rm /lib/modules/2.6.X-Y-386/kernel/drivers/usb/serial/ftdi_sio.ko
# cd /dev
# mknod -m 666 dmx0 c 180 192

Add the following line to /etc/modules so that the dmx_usb module is loaded on startup:

 dmx_usb.ko

Again, you can do this using nano

# nano /etc/modules

Finally reboot the machine

# reboot

Starting the Node

Login to the machine with your username and password

Check that the dmx_usb module is loaded:

$ lsmod | grep dmx_usb
dmx_usb                11012  0
usbcore               114176  8 dmx_usb,ftdi_sio,usbserial,usb_storage,usbhid,uhci_hcd,ehci_hcd

You should see two lines like above. This shows that the driver has been loaded correctly.

Plug in the Enttec Open DMX USB Interface. Run dmesg and check that the device was initialized corrected:

$ dmesg
   ... heaps of output ...
usb 3-1: new full speed USB device using uhci_hcd and address 5
usb 3-1: configuration #1 chosen from 1 choice
/home/simon/dmx_usb_module/dmx_usb.c: DMX USB device now attached to dmx192

Right at the end you should see something like the 3 lines above. This means that the widget has been recognised by the dmx_usb driver.

Start the artnet node by running:

$ artnet_usb

By default the node starts up using ArtNet subnet 0 and port 0, this corresponds to Universe 0 in Magic Q PC

Running artnet_usb with the -v option gives you debug information. The following arguments are supported:

 -a <ip-address>        IP address to listen on (defaults to the address
                        of the first non loopback interface)
 -c <config_file>       Config file to use for node name and port settings
 -d <dmx-device>        device for dmx output (default /dev/dmx0)
 -p <port-address>      port address for output universe (default 0)
 -s <subnet-address>    subnet address for output universe (default 0)
 -v                     be verbose (prints data for first four channels)
 -z                     Run in a new process (handles widget disconnects cleanly)

The universe address of the port is made up from the ArtNet subnet address and the ArtNet port address. The four least significant bits are the port address, the four most significant are the subnet address.

For example :

$ artnet-usb -p 3 -s 2

sets the universe address to 0x23

Testing with DMX Workshop

Start DMX Workshop and verify that the node appears in the connected devices list.

Using the node with Magic Q PC

If you enable now Artnet Universe 0 in Magic Q from ChamSys, you have a fully functioning one universe DMX512 interface. This works much better than MagicQ alone with the Open DMX USB Windows drivers. You can also use as many universes as ArtNet supports (but at the moment only one Open DMX USB device per node is supported)