Tutorial: ARI’s “Hello world”

Section

Developing applications - tutorials

🏁 Goal of this tutorial

By the end of this tutorial, you will know how to make ARI says a message in the language that you want with it voice.

Pre-requisites

• You should first have completed ARI’s unboxing

• This tutorial requires you to have Python3 installed.

• This tutorial requires you to have ROS noetic installed, if you don’t have it, use this link. Choose the desktop-full version of ROS, to have access to visual tools like rviz.

• This tutorial requires you to have pal_msgs package installed to use Tts. If you don’t have it, you will have to clone it (Here is the GitHub page)

The code

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

# System imports
import sys
import random

# ROS imports
import rospy

#actions
from actionlib import SimpleActionClient
from pal_interaction_msgs.msg import TtsAction, TtsGoal


def connection():
    tts_client = SimpleActionClient('/tts', TtsAction)
    tts_client.wait_for_server()
    return tts_client


if __name__ == '__main__':
    try:
        rospy.init_node('<node_name>')
        tts_client = connection()
        goal = TtsGoal()
        goal.rawtext.text = '<message>'
        goal.rawtext.lang_id = '<language>'
        tts.tts_client.send_goal_and_wait(goal)
    except rospy.ROSInterruptException:
        print("Abruptly finished!")

The code explained

The first method that you created is connection(), here you connect the TtsAction using the SimpleActionClient() function.

Then you wait until the server is connected with the wait_for_server().

Once you have TtsAction connected to the server, in the main function, you need to start the node that you are running, so you use the rospy.init_node() function with the name that you have put on your node.

Next step is to start a TtsGoal with the message and the language that you want the robot to talk. Here is an example to say “Hello” in English:

goal.rawtext.text = 'Hello'
goal.rawtext.lang_id = 'en_EN'

If you want to choose another language you have to put it in RFC 3066 format, here is a link to the reference.

For finishing the tutorial you will have to send the message, you need to do it with the send_goal_and_wait() function. This, sends the message and also waits until ARI has finished saying the message to keep running the script.

Next steps

• You can continue with the next ‘Beginners’ guide: 🚧 Tutorial: Creating a simple multi-modal interaction