In order to provide speech capabilities to the robots that do not have a Text-To-Speech system installed, but are equipped with microphones, the rapp_text_to_speech_espeak ROS node. This module utilizes the espeak speech synthesis library, as well as the mbrola project for altering the speech synthesis voices.

ROS Services

Text to speech

Service URL: /rapp/rapp_text_to_speech_espeak/text_to_speech_topic

Service type: ```bash #Contains info about time and reference Header header #The text to be spoken string text #The audio output file string audio_output #Language (en, gr)

string language

#Possible errors string error ```

It should be mentioned that there are cases where Espeak fails to produce the entirety of the given text as audio (for example if the input is a long sentence in Greek, it would probably create a shorter audio than the desired).

Launchers

Standard launcher

Launches the rapp_text_to_speech_espeak node and can be launched using ``` roslaunch rapp_text_to_speech_espeak text_to_speech_espeak.launch ```

Web services

URL

localhost:9001/hop/text_to_speech

Input / Output

``` Input = { “text”: “THE_TEXT_TO_BECOME_SPEECH” “language”: “THE_TEXT_LANGUAGE” } Output = { "payload": THE_AUDIO_DATA, "basename": "test.wav", "encoding": "base64", "error": "" } ```

The full documentation exists here