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Setting up ROS on RaspberryPi

Description: This is a simple how to for installing and setting up ROS on RaspberryPi

Keywords: RaspberryPi, Setup, ROS

Tutorial Level: BEGINNER

This is just a small how to re: getting ROS to work on the Raspberry Pi.

Note: This tutorial applies to ROS Fuerte. For Groovy, there are instructions for installing ROS either from source or from binary packages on Raspbian on groovy/Installation/Raspbian

Debian:Squeeze OS Set-up

Pi Setup

This tutorial will not go into a lot of detail re: the Pi set-up itself however the main thing is to boot the Pi with as much memory as possible. With that in mind set the arm224_start.elf to be your start.elf file.

Also ensure you have a reasonable amount of swap space available (The build of ROS is on the Pi itself)

Building ROS

This is largely following the Debian Instruction here With a few notable exceptions:

• The current version of raspbian doesn't have pip. Pip in the raspbian repo wants python 2.6 instead of python2.7. To get pip for 2.7 type

  sudo easy_install pip

• Update the turtle.cpp file to the attached one - else compilation problems (static_cast<> issue around std::max()). The updated version can be found here:turtle.txt

• Use just make and not "make -j8" - it's a single core machine and all 8 cpp threads will do it hang everything on waiting on IO - trust me I tried - 8 hrs later and still nothing... This step takes somewhere between 1-2 hrs.

• Before Section 1.5 (Build Higher Level Tools) type .

  export ROS_OS_OVERRIDE=debian:squeeze

  is it mentioned later in the install. I found you need it sooner. If after this rosdep throws an error during Step 1.5 (when executing rosdep install -a) about not being able to identify OS then it will be necessary to use the following instead

  rosdep install -ay --os=debian:squeeze

Then Finish off

Note: At the time of writing re: section 1.5 "rosdep install -a". There are problems with this. However these are the higher level functions that might be too much for the Pi. However it will certainly work as remote IO nodes around on a robot for lower level processing.

Once complete done you should be able to run ROS. Below is a screen shot of rxconsole; turtlesim etc with a move command being published (from the tutorials).

A word of expectation it's slow. I expect the graphics drivers will have much to do with it (which are due to be changed to take advantage of the GPU).

To get the tutorial running open 3 terminal windows.

• In window 1 enter

  roscore

• In window 2 enter (this will bring-up the turtlesim window)

  rosrun turtlesim turtlesim_node

• In window 3 enter (this will enable you to control the turtle in the turtlesim window using your keyboard - so long as window 3 is in focus / selected).

  rosrun turtlesim turtle_teleop_key

Raspbian OS

During build You may run into a error that looks like this.

• "/ros-underlay/rx/rxtools/src/rxtools/rxtools.i:2: Error: Unable to find 'std_string.i'"

swig was installed to the wrong folder you must move it. Use the following command from root directory.

• cp -r /swig /usr/local/share

The Raspbian OS has /tmp set up to be in RAM. To fix it this:

• In .bashrc, add: export TMPFS=/var/tmp
• Then edit /etc/default/rcS and comment out the line that reads: RAMPTMP=yes
• Reboot.

Additionally, it appears there was some sort of error in the install scripts that placed ROS in /opt/ros/fuert not in /opt/ros/fuerte.

To Fix Do a: sudo mv /opt/ros/fuert /opt/ros/fuerte to rename it, after performing step 1.3.2, and then repeat 1.3.2 to get it to put everything in the right place.

ROS Peripherals

This section details how to build some of the interfaces on the Pi

usb_cam

Firstly get the usb_cam driver from svn:

$ cd <some ros workspace>
$ svn co https://bosch-ros-pkg.svn.sourceforge.net/svnroot/bosch-ros-pkg/trunk/stacks/bosch_drivers
$ rospack profile
$ roscd usb_cam 

Then install the prerequisite packages:

$ sudo apt-get install libavcodec-dev 
$ sudo apt-get install libswscale-dev
$ sudo apt-get install libtinyxml-dev
$ cd <some ros workspace> 
$ rosmake

Finally test using

$ rosrun usb_cam usb_cam_node

usb_cam will use about 60% on the latest hard-float release (as of 8th Oct 2012)

GPIO Interface

To Do

This is a place holder for what I expect would be a ROS node to interface with the GPIO interface on the Pi....