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## note.0= [[kobuki/Tutorials/Installation|Kobuki Installation]]
## descriptive title for the tutorial
## title = Examine Kobuki
## multi-line description to be displayed in search 
## description =  Start up your Kobuki and see what's going on inside.
## the next tutorial description (optional)
## next = 
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## next.0.link=[[kobuki/Tutorials/Diagnostics|Kobuki Diagnostics]] 
## what level user is this tutorial for 
## level= BeginnerCategory
## keywords = kobuki, start, examine, roslaunch, rostopic
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<<IncludeCSTemplate(TutorialCSHeaderTemplate)>>

<<Version()>>

<<Version(groovy)>>

<<TableOfContents(4)>>

= Overview =

In this tutorial you will learn how to start the basic software for Kobuki, inspect the sensors' state and send commands.

= Launch Kobuki =

First, start minimal.launch to bring up Kobuki's basic software (bootstrap layer). We use the argument ''--screen'' to get verbose output in the terminal.

{{{
> roslaunch kobuki_node minimal.launch --screen
}}}

This launch file starts a nodelet manager and loads the Kobuki nodelet (the ROS wrapper around Kobuki's driver).

= Examine the topics =
Next, take a look at Kobuki's topics.

{{{
$ rostopic list
/diagnostics
/diagnostics_agg
/diagnostics_toplevel_state
/joint_states
/mobile_base/commands/digital_output
/mobile_base/commands/external_power
/mobile_base/commands/led1
/mobile_base/commands/led2
/mobile_base/commands/motor_power
/mobile_base/commands/reset_odometry
/mobile_base/commands/sound
/mobile_base/commands/velocity
/mobile_base/debug/raw_data_command
/mobile_base/debug/raw_data_stream
/mobile_base/events/bumper
/mobile_base/events/button
/mobile_base/events/cliff
/mobile_base/events/digital_input
/mobile_base/events/power_system
/mobile_base/events/robot_state
/mobile_base/events/wheel_drop
/mobile_base/sensors/bump_pc
/mobile_base/sensors/core
/mobile_base/sensors/dock_ir
/mobile_base/sensors/imu_data
/mobile_base/sensors/imu_data_raw
/mobile_base/version_info
/odom
/rosout
/rosout_agg
/tf
}}}

{{{{#!wiki version hydro
In Hydro, a couple of new topics joined the list:

{{{
/mobile_base/commands/controller_info
/mobile_base/controller_info
}}}
}}}}

As you see, Kobuki's data in- and output follows a structure:

 * ''<node_name>/sensor/'': Continuous streams of the sensor's data (note that /odom and /joints_states are remapped by default, since they are widley used at the highest level/namespace)
 * ''<node_name>/events/'': If a sensor changes its state, e.g. bumper pressed/released, the new state is published here.
 * ''<node_name>/commands/'': Use these topics to make Kobuki do things like switch on LEDs, playing sounds and driving around.
 * ''<node_name>/debug/'': Outputs detailed info about a lot of Kobuki's internals.

== Check sensors ==

Let's try out some topics.

 * Check the bumpers: Listen to the bumper topic, then tap one of the bumpers.
 {{{
$ rostopic echo /mobile_base/events/bumper 
state: 1
bumper: 2
---
state: 0
bumper: 2
---
}}}
 * Check the wheel drop sensors: Listen to the wheel drop sensor topic, then lift up and put down Kobuki.
 {{{
$ rostopic echo /mobile_base/events/wheel_drop 
state: 1
wheel: 0
---
state: 1
wheel: 1
---
state: 0
wheel: 0
---
state: 0
wheel: 1
---
}}}
 * Check the IMU: Listen to the imu sensor topic, then turn Kobuki.
 {{{
$ rostopic echo /mobile_base/sensors/imu_data
header: 
  seq: 0
  stamp: 
    secs: 1355022789
    nsecs: 36483345
  frame_id: gyro_link
orientation: 
  x: 0.0
  y: 0.0
  z: 0.28769484546
  w: 0.957722128749
orientation_covariance: [1.7976931348623157e+308, 0.0, 0.0, 0.0, 1.7976931348623157e+308, 0.0, 0.0, 0.0, 0.005]
angular_velocity: 
  x: 0.0
  y: 0.0
  z: 0.000349065850399
angular_velocity_covariance: [1.7976931348623157e+308, 0.0, 0.0, 0.0, 1.7976931348623157e+308, 0.0, 0.0, 0.0, 0.005]
linear_acceleration: 
  x: 0.0
  y: 0.0
  z: 0.0
linear_acceleration_covariance: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
---
}}}

== Trigger stuff ==

Roboticists want to ''do'' things. So, let's do it!

'''Remark''': ''rostopic pub'' works create with tab completion!

 * Change the color or turn off a LED: Publish to the LED command topic. The available commands are:
   * 0 - off
   * 1 - green
   * 2 - orange
   * 3 - red
 For example:
 {{{
$ rostopic pub /mobile_base/commands/led1 kobuki_msgs/Led "value: 1"
$ rostopic pub /mobile_base/commands/led1 kobuki_msgs/Led "value: 0"
}}}

 * Play a sound: Publish to the sound command topic. The available sequences are:
   * 0 - turn on
   * 1 - turn off
   * 2 - recharge start
   * 3 - press button,
   * 4 - error sound
 and the nostalgic section...
   * 5 - start cleaning
   * 6 - cleaning end
 For example:
 {{{
$ rostopic pub /mobile_base/commands/sound kobuki_msgs/Sound "value: 6"
}}}

 * Make the turtle snap!: Publish to the velocity command topic.
 {{{
rostopic pub /mobile_base/commands/velocity geometry_msgs/Twist "linear:
  x: 0.1
  y: 0.0
  z: 0.0
angular:
  x: 0.0
  y: 0.0
  z: 0.0"
}}}

= What's next =

Now that you know how to launch the basics and work with Kobuki, it's time to [[kobuki/Tutorials/Make it move|take it for a ride]].

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## TutorialCategory
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