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Update CircuitPython_I2S_Tone.py

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* Fixed issue with sine wave calculation where changing the frequency did not have the correct result
* The DC offset would change based on the `tone_volume` var, now it is constant at `2**15-1`. 
* Added sample rate variable to make sine wave generation more parametric.
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papahabla 2019-02-25 10:03:07 -08:00 committed by GitHub
parent d4118459c0
commit 67cff596ba
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1 changed files with 5 additions and 4 deletions
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Adafruit_MAX98357/CircuitPython_I2S_Tone.py
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@ -5,12 +5,13 @@ import audioio
import board
import audiobusio
tone_volume = 0.1 # Increase this to increase the volume of the tone.
sample_rate = 8000
tone_volume = .1 # Increase or decrease this to adjust the volume of the tone.
frequency = 440 # Set this to the Hz of the tone you want to generate.
length = 8000 // frequency
length = sample_rate // frequency # One freqency period
sine_wave = array.array("H", [0] * length)
for i in range(length):
sine_wave[i] = int((1 + math.sin(math.pi * 2 * i / 18)) * tone_volume * (2 ** 15))
sine_wave[i] = int((math.sin(math.pi * 2 * frequency * i / sample_rate) * tone_volume + 1) * (2 ** 15 - 1))
# For Feather M0 Express, ItsyBitsy M0 Express, Metro M0 Express
audio = audiobusio.I2SOut(board.D1, board.D0, board.D9)
@ -18,7 +19,7 @@ audio = audiobusio.I2SOut(board.D1, board.D0, board.D9)
# audio = audiobusio.I2SOut(board.D1, board.D10, board.D11)
# For Metro M4 Express
# audio = audiobusio.I2SOut(board.D3, board.D9, board.D8)
sine_wave_sample = audioio.RawSample(sine_wave)
sine_wave_sample = audioio.RawSample(sine_wave, sample_rate=sample_rate)
while True:
audio.play(sine_wave_sample, loop=True)