103 lines
3.3 KiB
Python
103 lines
3.3 KiB
Python
# SPDX-FileCopyrightText: 2020 Jeff Epler for Adafruit Industries
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#
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# SPDX-License-Identifier: MIT
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"""Waterfall FFT demo adapted from
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https://teaandtechtime.com/fft-circuitpython-library/
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to work with ulab on Adafruit CLUE"""
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import array
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import board
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import audiobusio
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import displayio
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from ulab import numpy as np
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from ulab.scipy.signal import spectrogram
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display = board.DISPLAY
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# Create a heatmap color palette
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palette = displayio.Palette(52)
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for i, pi in enumerate((0xff0000, 0xff0a00, 0xff1400, 0xff1e00,
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0xff2800, 0xff3200, 0xff3c00, 0xff4600,
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0xff5000, 0xff5a00, 0xff6400, 0xff6e00,
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0xff7800, 0xff8200, 0xff8c00, 0xff9600,
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0xffa000, 0xffaa00, 0xffb400, 0xffbe00,
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0xffc800, 0xffd200, 0xffdc00, 0xffe600,
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0xfff000, 0xfffa00, 0xfdff00, 0xd7ff00,
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0xb0ff00, 0x8aff00, 0x65ff00, 0x3eff00,
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0x17ff00, 0x00ff10, 0x00ff36, 0x00ff5c,
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0x00ff83, 0x00ffa8, 0x00ffd0, 0x00fff4,
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0x00a4ff, 0x0094ff, 0x0084ff, 0x0074ff,
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0x0064ff, 0x0054ff, 0x0044ff, 0x0032ff,
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0x0022ff, 0x0012ff, 0x0002ff, 0x0000ff)):
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palette[51-i] = pi
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class RollingGraph(displayio.TileGrid):
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def __init__(self, scale=2):
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# Create a bitmap with heatmap colors
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self._bitmap = displayio.Bitmap(display.width//scale,
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display.height//scale, len(palette))
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super().__init__(self._bitmap, pixel_shader=palette)
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self.scroll_offset = 0
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def show(self, data):
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y = self.scroll_offset
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bitmap = self._bitmap
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board.DISPLAY.auto_refresh = False
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offset = max(0, (bitmap.width-len(data))//2)
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for x in range(min(bitmap.width, len(data))):
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bitmap[x+offset, y] = int(data[x])
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board.DISPLAY.auto_refresh = True
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self.scroll_offset = (y + 1) % self.bitmap.height
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group = displayio.Group(scale=3)
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graph = RollingGraph(3)
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fft_size = 256
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# Add the TileGrid to the Group
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group.append(graph)
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# Add the Group to the Display
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display.root_group = group
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# instantiate board mic
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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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#use some extra sample to account for the mic startup
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samples_bit = array.array('H', [0] * (fft_size+3))
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# Main Loop
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def main():
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max_all = 10
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while True:
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mic.record(samples_bit, len(samples_bit))
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samples = np.array(samples_bit[3:])
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spectrogram1 = spectrogram(samples)
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# spectrum() is always nonnegative, but add a tiny value
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# to change any zeros to nonzero numbers
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spectrogram1 = np.log(spectrogram1 + 1e-7)
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spectrogram1 = spectrogram1[1:(fft_size//2)-1]
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min_curr = np.min(spectrogram1)
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max_curr = np.max(spectrogram1)
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if max_curr > max_all:
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max_all = max_curr
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else:
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max_curr = max_curr-1
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print(min_curr, max_all)
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min_curr = max(min_curr, 3)
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# Plot FFT
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data = (spectrogram1 - min_curr) * (51. / (max_all - min_curr))
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# This clamps any negative numbers to zero
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data = data * np.array((data > 0))
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graph.show(data)
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main()
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