talker-node.md

Overview

This week, we built a ROS node that subscribes to a new topic, /things_to_say, and uses a text-to-speech service to make the computer speak the messages of type std_msgs/String.

Prerequisite

If you receive an error when you try to run this node, the computer likely does not have pyttsx installed. To install it, simply run pip install pyttsx --user.

If that command fails, the computer likely does not have pip installed. To install it, run sudo apt-get install python-pip and then attempt the pyttsx install again.

Running the node

To run the node, run rosrun cr_ros talk.py

Making it talk

Once the node is launched, publish a String to the /things_to_say topic from any device connected to the same ROS core as the node.

Sample standalone command: rostopic pub /things_to_say std_msgs/String 'Kill all humans'

Sample Python script:

import rospy
from std_msgs import String

pub = rospy.Publisher('/things_to_say', String, queue_size=1)
rospy.init_node('say_something')
pub.publish('Kill all humans')

Ari Carr and Ben Albert 10/31/2018