137 lines
4.3 KiB
Python
137 lines
4.3 KiB
Python
# The MIT License (MIT)
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#
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# Copyright (c) 2017 Dan Halbert for Adafruit Industries
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# Copyright (c) 2017 Kattni Rembor, Tony DiCola for Adafruit Industries
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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import array
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import math
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import audiobusio
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import board
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import neopixel
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# Exponential scaling factor.
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# Should probably be in range -10 .. 10 to be reasonable.
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CURVE = 2
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SCALE_EXPONENT = math.pow(10, CURVE * -0.1)
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PEAK_COLOR = (100, 0, 255)
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NUM_PIXELS = 10
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# Number of samples to read at once.
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NUM_SAMPLES = 160
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# Restrict value to be between floor and ceiling.
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def constrain(value, floor, ceiling):
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return max(floor, min(value, ceiling))
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# Scale input_value between output_min and output_max, exponentially.
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def log_scale(input_value, input_min, input_max, output_min, output_max):
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normalized_input_value = (input_value - input_min) / \
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(input_max - input_min)
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return output_min + \
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math.pow(normalized_input_value, SCALE_EXPONENT) \
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* (output_max - output_min)
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# Remove DC bias before computing RMS.
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def normalized_rms(values):
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minbuf = int(mean(values))
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samples_sum = sum(
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float(sample - minbuf) * (sample - minbuf)
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for sample in values
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)
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return math.sqrt(samples_sum / len(values))
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def mean(values):
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return sum(values) / len(values)
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def volume_color(volume):
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return 200, volume * (255 // NUM_PIXELS), 0
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# Main program
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# Set up NeoPixels and turn them all off.
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pixels = neopixel.NeoPixel(board.NEOPIXEL, NUM_PIXELS,
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brightness=0.1, auto_write=False)
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pixels.fill(0)
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pixels.show()
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# For CircuitPython 2.x:
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mic = audiobusio.PDMIn(board.MICROPHONE_CLOCK, board.MICROPHONE_DATA,
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frequency=16000, bit_depth=16)
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# For Circuitpython 3.0 and up, "frequency" is now called "sample_rate".
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# Comment the lines above and uncomment the lines below.
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#mic = audiobusio.PDMIn(board.MICROPHONE_CLOCK, board.MICROPHONE_DATA,
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# sample_rate=16000, bit_depth=16)
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# Record an initial sample to calibrate. Assume it's quiet when we start.
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samples = array.array('H', [0] * NUM_SAMPLES)
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mic.record(samples, len(samples))
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# Set lowest level to expect, plus a little.
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input_floor = normalized_rms(samples) + 10
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# OR: used a fixed floor
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# input_floor = 50
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# You might want to print the input_floor to help adjust other values.
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# print(input_floor)
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# Corresponds to sensitivity: lower means more pixels light up with lower sound
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# Adjust this as you see fit.
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input_ceiling = input_floor + 500
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peak = 0
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while True:
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mic.record(samples, len(samples))
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magnitude = normalized_rms(samples)
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# You might want to print this to see the values.
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# print(magnitude)
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# Compute scaled logarithmic reading in the range 0 to NUM_PIXELS
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c = log_scale(constrain(magnitude, input_floor, input_ceiling),
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input_floor, input_ceiling, 0, NUM_PIXELS)
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# Light up pixels that are below the scaled and interpolated magnitude.
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pixels.fill(0)
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for i in range(NUM_PIXELS):
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if i < c:
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pixels[i] = volume_color(i)
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# Light up the peak pixel and animate it slowly dropping.
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if c >= peak:
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peak = min(c, NUM_PIXELS - 1)
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elif peak > 0:
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peak = peak - 1
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if peak > 0:
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pixels[int(peak)] = PEAK_COLOR
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pixels.show()
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