Erle-Brain 2, controlling status LEDs with ROS

This tutorial explains how to control the status LEDs from Erle-Brain 2 with the Robot Operating System (ROS).

Connecting to Erle-Brain 2

There're several ways to access Erle-Brain 2 but let's assume that you've purchased the WiFi dongle adapter and the brain itself is creating a WiFi network. Connect to it by using the password: holaerle.

Once connected, type:

ssh erle@10.0.0.1

and use again the same password: holaerle.

Creating the catkin workspace

We'll user a new ROS catkin workspace for this tutorial:

cd ~/
mkdir -p hackster_catkin_ws/src
cd hackster_catkin_ws/src
catkin_init_workspace

That's it, a new ROS workspace has been created.

Cloning the code and compiling it

cd ~/hackster_catkin_ws/src
git clone https://github.com/erlerobot/ros_erle_statusled 
cd cd ~/hackster_catkin_ws
catkin_make

which should give you something like:

erle@erle-brain-2 ~/hackster_catkin_ws $ catkin_make
Base path: /home/erle/hackster_catkin_ws
Source space: /home/erle/hackster_catkin_ws/src
Build space: /home/erle/hackster_catkin_ws/build
Devel space: /home/erle/hackster_catkin_ws/devel
Install space: /home/erle/hackster_catkin_ws/install
####
#### Running command: "cmake /home/erle/hackster_catkin_ws/src -DCATKIN_DEVEL_PREFIX=/home/erle/hackster_catkin_ws/devel -DCMAKE_INSTALL_PREFIX=/home/erle/hackster_catkin_ws/install -G Unix Makefiles" in "/home/erle/hackster_catkin_ws/build"
####
-- Using CATKIN_DEVEL_PREFIX: /home/erle/hackster_catkin_ws/devel
-- Using CMAKE_PREFIX_PATH: /home/erle/ros_catkin_ws/devel_isolated/rosbag;/home/erle/ros_catkin_ws/install_isolated
-- This workspace overlays: /home/erle/ros_catkin_ws/devel_isolated/rosbag;/home/erle/ros_catkin_ws/install_isolated
-- Using PYTHON_EXECUTABLE: /usr/bin/python
-- Using Debian Python package layout
-- Using empy: /usr/bin/empy
-- Using CATKIN_ENABLE_TESTING: ON
-- Call enable_testing()
-- Using CATKIN_TEST_RESULTS_DIR: /home/erle/hackster_catkin_ws/build/hackster_results
-- gtest not found, C++ tests can not be built. Please install the gtest headers globally in your system or checkout gtest (by running 'svn checkout http://googletest.googlecode.com/svn/tags/release-1.6.0 gtest' in the source space '/home/erle/hackster_catkin_ws/src' of your workspace) to enable gtests
-- Using Python nosetests: /usr/bin/nosetests-2.7
-- catkin 0.6.15
-- BUILD_SHARED_LIBS is on
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- ~~  traversing 1 packages in topological order:
-- ~~  - ros_erle_statusled
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- +++ processing catkin package: 'ros_erle_statusled'
-- ==> add_subdirectory(ros_erle_statusled)
-- Using these message generators: gencpp;genlisp;genpy
-- Configuring done
-- Generating done
-- Build files have been written to: /home/erle/hackster_catkin_ws/build
####
#### Running command: "make -j4 -l4" in "/home/erle/hackster_catkin_ws/build"
####

Trying it out

Let's launch our ROS package and give it a try:

sudo -s # you'll need privileges since we're accessing /dev/mem
cd ~/hackster_catkin_ws
source devel/setup.bash 
rosrun ros_erle_statusled statusleds.py

All right, ROS package launched, now from another terminal, type:

rostopic pub /statusleds std_msgs/String "blue"