Python Snippets
===============

------------------------
Use Azure speech backend
------------------------

``robot.say()`` uses ``acapela`` by default. To use ``azure`` instead:

.. code-block:: python

    import asyncio
    import navel

    async def main():
        async with navel.Robot() as robot:
            robot.set_speech_backend(
                "azure",
                speech_key="...",
                speech_region="...",
                locale="en-US",
                voice_name="en-US-AvaMultilingualNeural",
            )
            await robot.say("Hello from Azure.")

    if __name__ == "__main__":
        asyncio.run(main())


.. _system_volume:

------------------
Set speaker volume
------------------

.. code-block:: python

    import navel
    
    with navel.Robot() as robot:
        print(f"Previous volume: {robot.volume}%")
        robot.volume += 3
        print(f"New volume: {robot.volume}%")


--------------------------
Stream audio to Google ASR
--------------------------

In your virtual environment, ``pip install pyaudio``.

Follow examples on `Github <https://github.com/GoogleCloudPlatform/python-docs-samples/blob/main/speech/microphone/transcribe_streaming_infinite.py>`_.

You can configure what microphone to use by adding an ``input_device_index`` in ``self._audio_interface.open()``.

To list the available devices with indices, use the following code.

.. code-block:: python

    import pyaudio
    p = pyaudio.PyAudio()
    for i in range(p.get_device_count()):
        print(p.get_device_info_by_index(i))


------------------------------------
Disable automatic facial expressions
------------------------------------

Facial expressions are in auto-mode by default, which weakens your manual
control. You can disable it until restart with the following code.

.. code-block:: python

    import navel

    with navel.Robot() as robot:
        robot.config_set("cns_fer_cont_t1", 0, navel.DataType.U32)
        robot.config_set("cns_fer_cont_t2", 0, navel.DataType.U32)
        robot.config_set("cns_fer_peak_t1", 0, navel.DataType.U32)
        robot.config_set("cns_fer_peak_t2", 0, navel.DataType.U32)
        robot.config_set("cns_fer_overlay_inc", 0, navel.DataType.F32)
        robot.config_set("cns_fer_overlay_max", 0, navel.DataType.F32)
        robot.config_set("cns_fer_overlay_peak_min", 0, navel.DataType.F32)
        robot.config_set("cns_fer_peak_max", 0, navel.DataType.F32)


-----------------
Read camera frame
-----------------

Use ``HeadCamera`` or ``ChestCamera`` to fetch a single RGB frame on demand.
Frames are returned as ``numpy.ndarray`` in HWC format
(``height x width x 3``) with ``uint8`` values. The frame timestamp is in
microseconds.

.. code-block:: python

    import os
    import time
    from datetime import datetime
    
    from navel import ChestCamera, HeadCamera
    
    
    SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
    OUT_DIR = os.path.join(SCRIPT_DIR, "camera_frames")
    
    
    def _write_ppm(path, data, width, height):
        header = f"P6\n{width} {height}\n255\n".encode("ascii")
        with open(path, "wb") as f:
            f.write(header)
            f.write(data.tobytes())
    
    
    def _write_frame(prefix, out_dir, frame):
        ts = datetime.fromtimestamp(frame.timestamp_us / 1_000_000)
        stamp = ts.strftime("%Y%m%d_%H%M%S_%f")
        path = os.path.join(out_dir, f"{prefix}_{stamp}.ppm")
        _write_ppm(path, frame.data, frame.width, frame.height)
        print(f"wrote {path}")
    
    
    if __name__ == "__main__":
        os.makedirs(OUT_DIR, exist_ok=True)
    
        try:
            with HeadCamera() as head_cam, ChestCamera() as chest_cam:
                while True:
                    head_frame = head_cam.get_frame(timeout_ms=500)
                    _write_frame("head", OUT_DIR, head_frame)
    
                    chest_frame = chest_cam.get_frame(timeout_ms=500)
                    _write_frame("chest", OUT_DIR, chest_frame)
    
                    time.sleep(1.0)
        except KeyboardInterrupt:
            pass


-------
Driving
-------

With this example, the robot drives forward and backward in a loop. Make sure
the robot has clear space and is safe to move before running it.

.. code-block:: python

    #!/usr/bin/env python3
    
    import asyncio
    import navel
    
    async def drive(robot: navel.Robot, cycles: int = 2):
        for i in range(cycles):
            print(f"{i} forwards")
            await robot.move_base(2, speed=0.5)
            print(f"{i} backwards")
            await robot.move_base(-2, speed=0.5)
    
    async def main():
        async with navel.Robot() as robot:
            await drive(robot, cycles=2)
    
    if __name__ == "__main__":
        asyncio.run(main())