This howto would not be possible without the guys from the XBMC forums.

In particular thanks need to go to
CharlesNasi for the original guide
Bob for the fantastic Boblight utility
The creators of CombustD
jaaps for some modifications to Boblight specific to amBX

If you cant get the files from their official sources you can get boblight and ruby usb here:
Note: There is a file embedded within this post, please visit this post to download the file.

Changelog

2010-05-22 – Initial draft published
2010-06-07 – Updated step 4 and 10 to use combustd 0.2 rather than 0.1 and removed step 11 as depreciated.
2010-06-07 – Removed libc6-dev-i386 as it breaks installation but doesn’t seem to be needed.

Ok so lets start

Getting started

1. First open a terminal, either Ctrl + Alt + F1 in xbmc or ssh into the machine
2. Create a working directory and move into it

   mkdir ambx
   cd ambx

3. (If not installed) install Subversion

   sudo apt-get install subversion

4. get combustd from svn

   svn checkout http://combustd.googlecode.com/svn/branches/combustd-ruby-0.2

5. Download Boblight and extract it to something you want, there is an svn version on googlecode, but i couldnt get it to make

   wget http://www.xs4all.nl/~loosen/boblight/boblight-1.3.tar.gz
   tar zxvf boblight-1.3.tar.gz

6. Get dependencies to compile Boblight, if you have any issues try one package at a time to find the problem, also some of these packages were already installed, can’t remember which ones though.

   sudo apt-get update
   sudo apt-get install gcc libusb-dev ruby ruby-dev libportaudio-dev libavdevice-dev libswscale-dev libavformat-dev libavcodec-dev libxrender-dev libsdl1.2-dev libx11-dev

7. Build the package ‘Boblight’:

   cd boblight-1.3
   sudo ./configure
   sudo make
   sudo make install
   cd ..
   

8. Configure Boblight
   Open a text-editor, i use nano, but its up to you and edit the file ‘boblight.conf (It probably wont already exist, thats fine).

   sudo nano /etc/boblight.conf

   Add the following code into the file, this is courtesy of jaaps and allows use of all 5 lights, Z3rO also added some lines to allow adding things like proportional, satuation, black threshold in the config rather than on the commandline.

   [global]
   interface 127.0.0.1
   port 19333
   
   [device]
   name AmbX_Combust
   output "ruby /usr/local/combustd/applications/boblight/boblight.rb"
   channels 15
   type popen
   interval 20000
   
   [color]
   name red
   rgb FF0000
   
   [color]
   name green
   rgb 00FF00
   
   [color]
   name blue
   rgb 0000FF
   
   [light]
   name left
   color red AmbX_Combust 1
   color green AmbX_Combust 2
   color blue AmbX_Combust 3
   hscan 0 33.33
   vscan 0 66.66
   saturation 3.0
   proportional 20.0
   value 3
   threshold 20
   interpolation on
   
   [light]
   name right
   color red AmbX_Combust 4
   color green AmbX_Combust 5
   color blue AmbX_Combust 6
   hscan 66.66 100
   vscan 0 66.66
   saturation 3.0
   proportional 20.0
   value 3
   threshold 20
   interpolation on
   
   [light]
   name wwleft
   color red AmbX_Combust 7
   color green AmbX_Combust 8
   color blue AmbX_Combust 9
   hscan 0 40
   vscan 0 33.33
   saturation 3.0
   proportional 20.0
   value 3
   threshold 20
   interpolation on
   
   [light]
   name wwright
   color red AmbX_Combust 10
   color green AmbX_Combust 11
   color blue AmbX_Combust 12
   hscan 60 100
   vscan 0 33.33
   saturation 3.0
   proportional 20.0
   value 3
   threshold 20
   interpolation on
   
   [light]
   name wwcenter
   color red AmbX_Combust 13
   color green AmbX_Combust 14
   color blue AmbX_Combust 15
   hscan 33 66
   vscan 0 33.33
   saturation 3.0
   proportional 20.0
   value 3
   threshold 20
   interpolation on

   Save the file and exit. (Ctrl + O then Ctrl + X)

   If you are hiding the left and right lights behind the TV, use value 15 on the appropriate lines of the config as above, if you aren’t then use value 3, value sets how bright the lights are.

   Boblight is now configured.

9. Download, Install and compile Ruby-usb

   wget http://www.a-k-r.org/ruby-usb/ruby-usb-0.2.tar.gz
   tar -zxvf ruby-usb-0.2.tar.gz
   cd ruby-usb-0.2
   sudo ruby extconf.rb
   sudo make && sudo make install
   cd ..
   

10. CombustD

    sudo mv combustd-ruby-0.2 /usr/local/combustd

Running boblight

That should be everything configured, now start the daemon.

sudo boblightd

Test if its working

boblight-constant ff00ff; sleep 5; killall boblight-constant

All the lights should come on for 5 seconds (they will be a pinky color) then go off.

Time to start the magic

boblight-X11 -s 5 -t 0.1 -a 20 -v 3
boblight-X11 -t 0.1

This starts the binary, sets the saturation to 5, the interval between refreshes to 0.1 seconds, brightness to 3 and the speed to 20 and sets the interval between refreshes to 0.1 seconds (the other options aren’t needed as they are now set in the config). If you get an error about ERROR: Can’t open display (null) the DISPLAY environment variable isn’t set, just type:

export DISPLAY=:0.0

You will need to redo this when you reboot.

Boblight Configuration Options

You can change the way boblight works by supplying options, the list of options is:

boblight-X11 1.3

Usage: boblight-x11 [OPTION]
Start the X11 grabber for boblight

  -s	set the saturation
  -v	set the value
  -i	set the interpolation, use "-i on" or "-i off"
  -a	set the proportional
  -p	set the priority, default is 128
  -t	set the timer interval, default is 0.5 second,
  -u	set the lights to use, comma separated list
  -e	set the server address[:port]
  -g	grab n pixels on n lines
    	default is 100 for XShmGetImage and 16 for XGetImage
  -m	grab method, use "-m average" or "-m median"
  -x	use XGetImage instead of XShmGetImage (slow!)
  -b	set the black threshold

Todo.

Look into starting boblight on startup
Look into creating a boblight script for xbmc allowing users to change settings and start/stop through GUI
Add some pictures and a youtube video

Automatically starting amBX

By utilising udev we can set amBX to turn on when we press the power button on the amBX system, if you never turn the system off by the power button on the amBX unit, then the lights will automatically come on when xbmc boots.

Create a new udev rule:

sudo nano /etc/udev/rules.d/99-ambx.rules

Copy the code below into it and save:

SUBSYSTEM=="usb", ATTRS{idVendor}=="0471", ATTRS{idProduct}=="083f", ACTION=="add", RUN+="/usr/bin/startambx"

Create the startambx script:

sudo nano /usr/bin/startambx

Copy the code below into it and save:

#!/bin/sh
boblightd
sudo su - xbmc -c "DISPLAY=:0.0 boblight-X11 -t 0.1"

If you are using a username other than xbmc replace the instance above with the appropriate username.