Playing Sound

There are two main modules built-in to MicroHydra currently, which can be used for playing sound on the Cardputer.

lib.audio.Audio

MicroHydra's audio module subclasses the apropriate audio module for the current device (Currently this is only i2ssound, but may be expanded in the future), and initializes it with the apropriate values for the device.

Note:

i2ssound was previously named M5Sound, and was contributed by Lana-chan, for playing high-quality sound on the Cardputer.
It has been renamed for consistency with MicroHydras other modules.

It can play samples stored in a variable, or read large samples from storage using little memory.
It also can change the pitch of those samples, and even play several at the same time, overlapping.

basic usage example (ALSO provided by Lana-chan):

import time
from lib.audio import Audio

audio = Audio()

_SQUARE = const(\
    b'\x00\x80\x00\x80\x00\x80\x00\x80\x00\x80\x00\x80'\
    b'\x00\x80\x00\x80\x00\x80\x00\x80\x00\x80\x00\x80'\
    b'\x00\x80\x00\x80\x00\x80\x00\x80\x00\x80\x00\x80'\
    b'\x00\x80\x00\x80\xFF\x7F\xFF\x7F\xFF\x7F\xFF\x7F'\
    b'\xFF\x7F\xFF\x7F\xFF\x7F\xFF\x7F\xFF\x7F\xFF\x7F'\
    b'\xFF\x7F\xFF\x7F\xFF\x7F\xFF\x7F\xFF\x7F\xFF\x7F'\
    b'\xFF\x7F\xFF\x7F\xFF\x7F\xFF\x7F\xFF\x7F\x00\x80'
)
SQUARE = memoryview(_SQUARE)

for note in range(24,60): # note values, C-3 to B-5
    audio.play(SQUARE, note, 0, 14, 0, True)
    for i in range(13,1,-1): # fade out volume
        audio.setvolume(i)
        time.sleep(0.05)
    audio.stop(0)

Samples can also be loaded from a 'raw' file on the flash or SDCard.

i2ssound.Sample(source, buffer_size=1024)
"""Initialize a sample for playback

- source: If string, filename. Otherwise, use MemoryView.
- buffer_size: If loading from filename, the size to buffer in RAM.
"""

---

beeper

beeper.py is a module for playing simple UI beeps.

This module is very imperfect. It is somewhat limited in its use, however, it is simple to use.

In previous versions, this module used its own, blocking, implementation for sending audio to the speaker. However, the current version is just a wrapper for the Audio class above. The audio is now much higher quality and more consistent, however there is a noticable delay in it. I would like to fix this in the future, but I'm not sure how to do that.

To use it:

from lib.hydra import beeper

#init the beeper!
beep = beeper.Beeper()

beep.play(
    # a tuple of strings containing notes to play. a nested tuple can be used to play multiple notes together.
    notes=('C4',('D4','D4')),
    # how long to play each note
    time_ms=120,
    # an integer from 0-10 representing the volume of the playback. Default is 2, 0 is almost inaudible, 10 is loud.
    volume=10,
)