Hardware Requirements

To use this package you need a Care-O-bot light modul connected via USB.


The cob_light package provides a node that connects to the light hardware board and offers a message interface over topics. The current state of the light is published as a visualization marker.


The cob_light.py node takes in std_msgs/ColorRGBA messages and send this directly to the hardware. If no hardware is present, the node runs in a simulated mode only publishing visualization markers.

Subscribed Topics

command (std_msgs/ColorRGBA)
  • Receives color commands in RGBA format.

Published Topics

marker (visualization_msgs/Marker)
  • Publishes the current state of the light.


~devicestring (string, default: Required)
  • Device identifier for hand, e.g. /dev/ttyUSB3
~baudrate (int, default: Required)
  • Baudrate of serial interface, e.g. 230400


The package can be used via a launch file which loads all parameters and starts the light node. For starting the light use

roslaunch cob_bringup light.launch

For including the light in your overall launch file use

<include file="$(find cob_bringup)/components/light.launch" />

A sample parameter file could look like this

devicestring: /dev/ttyUSB3
baudrate: 230400

For testing the light you can start a test_script which changes the LEDs to different colors.

rosrun cob_light test.py

Wiki: cob_light (last edited 2012-06-28 09:02:26 by FlorianWeisshardt)