A Python script managing a Google Voice Assistant living inside a rotary dial phone. Full write up at https://medium.com/@aallan/a-retro-rotary-phone-powered-by-aiy-projects-and-the-raspberry-pi-e516b3ff1528.

retro_phone.py

#!/usr/bin/env python3
#
# Full write up at https://medium.com/@aallan/a-retro-rotary-phone-powered-by-aiy-projects-and-the-raspberry-pi-e516b3ff1528.

import logging
import sys
import threading
import RPi.GPIO as GPIO
import pygame

import aiy.assistant.auth_helpers
import aiy.voicehat
from google.assistant.library import Assistant
from google.assistant.library.event import EventType

logging.basicConfig(
    level=logging.INFO,
    format="[%(asctime)s] %(levelname)s:%(name)s:%(message)s"
)

class MyAssistant(object):
    def __init__(self):
        self._task = threading.Thread(target=self._run_task)
        self._can_start_conversation = False
        self._assistant = None
		
        self._hook_is_down = 1;
        self._hook_up = aiy._drivers._button.Button(channel=4,polarity=GPIO.RISING)
        self._hook_up.on_press(self._handset_lifted)
        self._hook_down = aiy._drivers._button.Button(channel=17,polarity=GPIO.FALLING)
        self._hook_down.on_press(self._handset_replaced)

        pygame.mixer.init()
        pygame.mixer.music.load("/home/pi/Dial_Tone.wav")       

    def start(self):
        self._task.start()

    def _run_task(self):
        credentials = aiy.assistant.auth_helpers.get_assistant_credentials()
        with Assistant(credentials) as assistant:
            self._assistant = assistant
            for event in assistant.start():
                self._process_event(event)

    def _process_event(self, event):
        status_ui = aiy.voicehat.get_status_ui()
        if event.type == EventType.ON_START_FINISHED:
            status_ui.status('ready')
            self._can_start_conversation = True
            
            aiy.voicehat.get_button().on_press(self._on_button_pressed)
            if sys.stdout.isatty():
                print('Press the button, then speak. Press Ctrl+C to quit...')

        elif event.type == EventType.ON_CONVERSATION_TURN_STARTED:
            self._can_start_conversation = False
            status_ui.status('listening')

        elif event.type == EventType.ON_END_OF_UTTERANCE:
            status_ui.status('thinking')

        elif event.type == EventType.ON_CONVERSATION_TURN_FINISHED:
            status_ui.status('ready')
            self._can_start_conversation = True
            aiy.audio.play_wave("/home/pi/Hang_Up.wav")
            if self._hook_is_down == 0:
                 pygame.mixer.music.play(loops=-1)
 
        elif event.type == EventType.ON_ASSISTANT_ERROR and event.args and event.args['is_fatal']:
            sys.exit(1)

    def _handset_replaced(self):
       print('Hook down')
       self._hook_is_down = 1
       self._assistant.stop_conversation()
       pygame.mixer.music.stop()
       pygame.mixer.music.rewind()

    def _handset_lifted(self):
       print('Hook up')
       self._hook_is_down = 0
       pygame.mixer.music.play(loops=-1)

    def _on_button_pressed(self):
        if self._hook_is_down == 0:
           if self._can_start_conversation:
               pygame.mixer.music.stop()
               pygame.mixer.music.rewind()
               aiy.audio.say('Operator?')
               self._assistant.start_conversation()

def main():
    MyAssistant().start()

if __name__ == '__main__':
    main()