Successfully installed a 5DOF Dynamix AX-12 Turtlebot simplearm software in fuerte (instead of electric) by following Tutorial, http://www.ros.org/wiki/turtlebotarm/Tutorials/InstallationInstructions. controllerGUI.py commands the servos nicely. Question is which file to edit urdf description in the following section that applies to an electric installation as fuerte doesn't appear to use etc/ros/turtlebot nor bringup.launch.

1.3.3 Setting up the URDF

Next, we have to set up the TurtleBot's hardware description file (URDF) to include the arm. This is done through the TurtleBot bringup script in /etc/ros/turtlebot.

On the TurtleBot, edit /etc/ros/turtlebot/bringup.launch in your favorite text editor and change it to resemble this:

The line

tells the TurtleBot to use the urdf that includes the arm from the turtlebotarmdescription package.

Also rather than editing files per above in the write protected directories, such as /opt/ros/fuerte, is it advisable to put my custom "armbringup.launch" file such as in a ~/rosworkspace/my_arm/ directory?