diff --git a/3_HeyRobot/voice/Hey Robot.pmdl b/3_HeyRobot/voice/Hey Robot.pmdl
new file mode 100644
index 0000000..59e1f26
Binary files /dev/null and b/3_HeyRobot/voice/Hey Robot.pmdl differ
diff --git a/3_HeyRobot/voice/assistant_grpc_demo_snowboy.py b/3_HeyRobot/voice/assistant_grpc_demo_snowboy.py
new file mode 100644
index 0000000..241fd5b
--- /dev/null
+++ b/3_HeyRobot/voice/assistant_grpc_demo_snowboy.py
@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+# Copyright 2017 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""A demo of the Google Assistant GRPC recognizer."""
+
+import argparse
+import locale
+import logging
+import signal
+import sys
+from light import Light
+
+from aiy.assistant.grpc import AssistantServiceClientWithLed
+from aiy.board import Board
+from gpiozero import LED
+from gpiozero import PWMLED
+
+import mod.snowboydecoder as snowboydecoder
+
+def volume(string):
+    value = int(string)
+    if value < 0 or value > 100:
+        raise argparse.ArgumentTypeError('Volume must be in [0...100] range.')
+    return value
+
+def locale_language():
+    language, _ = locale.getdefaultlocale()
+    return language
+
+interrupted = False
+
+def signal_handler(signal, frame):
+    global interrupted
+    interrupted = True
+
+def interrupt_callback():
+    global interrupted
+    return interrupted
+
+def main():
+    logging.basicConfig(level=logging.DEBUG)
+    signal.signal(signal.SIGTERM, lambda signum, frame: sys.exit(0))
+
+    parser = argparse.ArgumentParser(description='Assistant service example.')
+    parser.add_argument('--language', default=locale_language())
+    parser.add_argument('--volume', type=volume, default=80)
+    parser.add_argument('--model', default='src/examples/voice/Hey Robot.pmdl')
+    args = parser.parse_args()
+
+    detector = snowboydecoder.HotwordDetector(args.model, sensitivity=0.5)
+    with Board() as board:
+        assistant = AssistantServiceClientWithLed(board=board,
+                                                  volume_percentage=args.volume,
+                                                  language_code=args.language)
+        while True:
+            #green_led = Light(18)
+            #red_led = Light(17)
+            logging.info('Speak own hotword and speak')
+            detector.start()
+            logging.info('Conversation started!')
+            assistant.conversation()
+
+
+if __name__ == '__main__':
+    main()
diff --git a/3_HeyRobot/voice/assistant_library_with_local_commands_demo.py b/3_HeyRobot/voice/assistant_library_with_local_commands_demo.py
new file mode 100644
index 0000000..482757e
--- /dev/null
+++ b/3_HeyRobot/voice/assistant_library_with_local_commands_demo.py
@@ -0,0 +1,90 @@
+#!/usr/bin/env python3
+# Copyright 2017 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Run a recognizer using the Google Assistant Library.
+
+The Google Assistant Library has direct access to the audio API, so this Python
+code doesn't need to record audio. Hot word detection "OK, Google" is supported.
+
+It is available for Raspberry Pi 2/3 only; Pi Zero is not supported.
+"""
+
+import logging
+import platform
+import subprocess
+import sys
+
+from google.assistant.library.event import EventType
+
+from aiy.assistant import auth_helpers
+from aiy.assistant.library import Assistant
+from aiy.board import Board, Led
+from aiy.voice import tts
+
+def power_off_pi():
+    tts.say('Good bye!')
+    subprocess.call('sudo shutdown now', shell=True)
+
+
+def reboot_pi():
+    tts.say('See you in a bit!')
+    subprocess.call('sudo reboot', shell=True)
+
+
+def say_ip():
+    ip_address = subprocess.check_output("hostname -I | cut -d' ' -f1", shell=True)
+    tts.say('My IP address is %s' % ip_address.decode('utf-8'))
+
+
+def process_event(assistant, led, event):
+    logging.info(event)
+    if event.type == EventType.ON_START_FINISHED:
+        led.state = Led.BEACON_DARK  # Ready.
+        print('Say "OK, Google" then speak, or press Ctrl+C to quit...')
+    elif event.type == EventType.ON_CONVERSATION_TURN_STARTED:
+        led.state = Led.ON  # Listening.
+    elif event.type == EventType.ON_RECOGNIZING_SPEECH_FINISHED and event.args:
+        print('You said:', event.args['text'])
+        text = event.args['text'].lower()
+        if text == 'power off':
+            assistant.stop_conversation()
+            power_off_pi()
+        elif text == 'reboot':
+            assistant.stop_conversation()
+            reboot_pi()
+        elif text == 'ip address':
+            assistant.stop_conversation()
+            say_ip()
+    elif event.type == EventType.ON_END_OF_UTTERANCE:
+        led.state = Led.PULSE_QUICK  # Thinking.
+    elif (event.type == EventType.ON_CONVERSATION_TURN_FINISHED
+          or event.type == EventType.ON_CONVERSATION_TURN_TIMEOUT
+          or event.type == EventType.ON_NO_RESPONSE):
+        led.state = Led.BEACON_DARK  # Ready.
+    elif event.type == EventType.ON_ASSISTANT_ERROR and event.args and event.args['is_fatal']:
+        sys.exit(1)
+
+
+def main():
+    logging.basicConfig(level=logging.INFO)
+
+    credentials = auth_helpers.get_assistant_credentials()
+    with Board() as board, Assistant(credentials) as assistant:
+        for event in assistant.start():
+            process_event(assistant, board.led, event)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/3_HeyRobot/voice/assistant_library_with_snowboy_demo.py b/3_HeyRobot/voice/assistant_library_with_snowboy_demo.py
new file mode 100644
index 0000000..8ff100f
--- /dev/null
+++ b/3_HeyRobot/voice/assistant_library_with_snowboy_demo.py
@@ -0,0 +1,135 @@
+#!/usr/bin/env python3
+# Copyright 2017 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Run a recognizer using the Google Assistant Library with button support.
+
+The Google Assistant Library has direct access to the audio API, so this Python
+code doesn't need to record audio. Hot word detection "OK, Google" is supported.
+
+It is available for Raspberry Pi 2/3 only; Pi Zero is not supported.
+"""
+
+import logging
+import platform
+import sys
+import threading
+
+import aiy.assistant.auth_helpers
+from aiy.assistant.library import Assistant
+import aiy.voicehat
+from google.assistant.library.event import EventType
+
+import mod.snowboydecoder as snowboydecoder
+
+if len(sys.argv) == 1:
+    print("Error: need to specify model name")
+    print("Usage: python demo.py your.model")
+    sys.exit(-1)
+
+model = sys.argv[1]
+
+logger = logging.getLogger("main")
+logging.basicConfig(
+    level=logging.INFO,
+    format="[%(asctime)s] %(levelname)s:%(name)s:%(message)s"
+)
+
+
+class MyAssistant(object):
+    """An assistant that runs in the background.
+
+    The Google Assistant Library event loop blocks the running thread entirely.
+    To support the button trigger, we need to run the event loop in a separate
+    thread. Otherwise, the on_button_pressed() method will never get a chance to
+    be invoked.
+    """
+
+    def __init__(self):
+        self._task = threading.Thread(target=self._run_task)
+        self._hotword = threading.Thread(target=self._run_hotword)
+        self._can_start_conversation = False
+        self._assistant = None
+
+    def start(self):
+        """Starts the assistant.
+
+        Starts the assistant event loop and begin processing events.
+        """
+        self._task.start()
+        self._hotword.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 _run_hotword(self):
+        detector = snowboydecoder.HotwordDetector(model, sensitivity=0.5)
+        with aiy.audio.get_recorder():
+            while True:
+                if self._can_start_conversation:
+                   detector.start(detected_callback=self._on_button_pressed,
+                                  interrupt_check=lambda: not(self._can_start_conversation),
+                                  sleep_time=0.03)
+                   detector.terminate()
+
+    def _process_event(self, event):
+        logger.debug(event)
+        status_ui = aiy.voicehat.get_status_ui()
+        if event.type == EventType.ON_START_FINISHED:
+            status_ui.status('ready')
+            self._can_start_conversation = True
+            # Start the voicehat button trigger.
+            aiy.voicehat.get_button().on_press(self._on_button_pressed)
+            if sys.stdout.isatty():
+                print('Say "OK, Google" or 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
+              or event.type == EventType.ON_CONVERSATION_TURN_TIMEOUT
+              or event.type == EventType.ON_NO_RESPONSE):
+            status_ui.status('ready')
+            self._can_start_conversation = True
+
+        elif event.type == EventType.ON_ASSISTANT_ERROR and event.args and event.args['is_fatal']:
+            sys.exit(1)
+
+    def _on_button_pressed(self):
+        # Check if we can start a conversation. 'self._can_start_conversation'
+        # is False when either:
+        # 1. The assistant library is not yet ready; OR
+        # 2. The assistant library is already in a conversation.
+        if self._can_start_conversation:
+            self._assistant.start_conversation()
+
+
+def main():
+    if platform.machine() == 'armv6l':
+        print('Cannot run hotword demo on Pi Zero!')
+        exit(-1)
+    MyAssistant().start()
+
+
+if __name__ == '__main__':
+    main()
diff --git a/3_HeyRobot/voice/light.py b/3_HeyRobot/voice/light.py
new file mode 100644
index 0000000..f4fd709
--- /dev/null
+++ b/3_HeyRobot/voice/light.py
@@ -0,0 +1,40 @@
+import RPi.GPIO as GPIO
+import time
+
+class Light(object):
+    def __init__(self, port):
+        self.port = port
+        GPIO.setmode(GPIO.BCM)
+        GPIO.setup(self.port, GPIO.OUT)
+        self.on_state = GPIO.HIGH
+        self.off_state = not self.on_state
+
+    def set_on(self):
+        GPIO.output(self.port, self.on_state)
+
+    def set_off(self):
+        GPIO.output(self.port, self.off_state)
+
+    def is_on(self):
+        return GPIO.input(self.port) == self.on_state
+
+    def is_off(self):
+        return GPIO.input(self.port) == self.off_state
+
+    def toggle(self):
+        if self.is_on():
+            self.set_off()
+        else:
+            self.set_on()
+
+    def blink(self, t=0.3):
+        self.set_off()
+        self.set_on()
+        time.sleep(t)
+        self.set_off()
+
+if __name__ == "__main__":
+    light = Light(17)
+    while True:
+        light.blink()
+        time.sleep(0.7)
diff --git a/3_HeyRobot/voice/voice_recorder.py b/3_HeyRobot/voice/voice_recorder.py
new file mode 100644
index 0000000..677d3a0
--- /dev/null
+++ b/3_HeyRobot/voice/voice_recorder.py
@@ -0,0 +1,36 @@
+import argparse
+import time
+import threading
+
+from aiy.board import Board
+from aiy.voice.audio import AudioFormat, play_wav, record_file, Recorder
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--filename', '-f', default='recording.wav')
+    args = parser.parse_args()
+
+    with Board() as board:
+        print('Press button to start recording.')
+        board.button.wait_for_press()
+
+        done = threading.Event()
+        board.button.when_pressed = done.set
+
+        def wait():
+            start = time.monotonic()
+            while not done.is_set():
+                duration = time.monotonic() - start
+                print('Recording: %.02f seconds [Press button to stop]' % duration)
+                time.sleep(0.5)
+
+        record_file(AudioFormat.CD, filename=args.filename, wait=wait, filetype='wav')
+        print('Press button to play recorded sound.')
+        board.button.wait_for_press()
+
+        print('Playing...')
+        play_wav(args.filename)
+        print('Done.')
+
+if __name__ == '__main__':
+    main()