ROS Tutorial

Build Environment

• Ubuntu
• ROS indigo
• python 2.7

Install ROS

Please check this page and install ROS to your PC that is installed ubuntu.

Create a Workspace

Please create a working directory to develop with ROS. After that, initialize the working directory environment as follows:

$ mkdir -p ~/catkin_ws/src
$ cd ~/catkin_ws/src
$ catkin_init_workspace
$ cd ~/catkin_ws
$ catkin_make

There is a setup script to initialize the environment. Please enter command below.

$ source ~/catkin_ws/devel/setup.bash

This process needs at first time whenever use ROS. Thus, I recommend to add script to .bashrc file.

#source /opt/ros/indigo/setup.bash
source ~/catkin_ws/devel/setup.bash

Create a Package

Please change directory and create a package.

$ cd ~/catkin_ws/src

$ catkin_create_pkg <YOUR_PACKAGE_NAME> rospy roscpp std_msgs

And then, run catkin_make again.

$ cd ~/catkin_ws
$ catkin_make
$ source ~/catkin_ws/devel/setup.bash

Now, your package can be available. Please check it with following command:

catkin_ws$ roscd <YOUR_PACKAGE_NAME>
catkin_ws/src/<YOUR_PACKAGE_NAME>$

If you can do it, creating a package is succeeded.

Connect to PLEN2

Since time of the shipment, PLEN2 has been access point mode (You could connect PLEN2 as WiFi). Also PLEN2 has been set different SSID and common password.

SSID: PLEN2dev<PLEN2_MAC_ADDRESS>
Password: plenproject

Setting Up ROS Environment

After connect your PC to PLEN2, please check IP address of your PC with ifconfig command. Then, change ROS environment parameters as follows:

export ROS_IP=<PC_IP_ADDRESS>
export ROS_HOSTNAME=<PC_IP_ADDRESS>
export ROS_MASTER_URI=http://192.168.42.1:11311

Now, your PC can communicate other ROS setuped devices.

Blink LED of PLEN2's Eyes

Let you blink LED of PLEN2's eyes. Please create following sample program.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import rospy
from std_msgs.msg import String


def talker():
    rospy.init_node('PCNode', anonymous=True)

    p = rospy.Publisher('PcToControl', String, queue_size=10)
    r = rospy.Rate(1)

    led_command = String()
    led_command.data = 'gpio,w,off'

    while ( not rospy.is_shutdown() ):
        if ( 'on' in led_command.data ):
            led_command.data = 'gpio,w,off'

        elif ( 'off' in led_command.data ):
            led_command.data = 'gpio,w,on'

        rospy.loginfo('%s', led_command.data)

        p.publish(led_command)
        r.sleep()


if __name__ == '__main__':
    try:
        talker()

    except rospy.ROSInterruptException:
        pass

This script blink PLEN2's eye at every seconds. PLEN2 subscribe topic which name is PcToControl.

You need to run following command to be availabel the python script:

$ chmod 755 <CREATED_SCRIPT_NAME>
$ python <CREATED_SCRIPT_NAME>

In addition, You could control PLEN2 with command below. See also...

serial,w,<ANY_PROTOCOL_OF_PLEN2>

For example, if you would like to play the motion that is placed slot 4, send command below:

serial,w,$pm04