Adding code for the RGB Matrix QT audio visualizer

Adding code for the RGB Matrix QT audio visualizer. Uses a Feather Sense to sample audio that is visualized with the RGB LEDs with ulab

Author: BlitzCityDIY

Feather_Sense_Audio_Visualizer_13x9_RGB_LED_Matrix/code.py

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+'''Adapted from the FFT Example: Waterfall Spectrum Analyzer
+by Jeff Epler
+https://learn.adafruit.com/ulab-crunch-numbers-fast-with-circuitpython/overview '''
+
+import array
+import board
+import audiobusio
+import busio
+from ulab import numpy as np
+from ulab.scipy.signal import spectrogram
+import adafruit_is31fl3741
+from adafruit_is31fl3741.adafruit_rgbmatrixqt import Adafruit_RGBMatrixQT
+
+#  Manually declare I2c (not board.I2C()) to access 1 MHz speed for
+i2c = busio.I2C(board.SCL, board.SDA, frequency=1000000)
+#  Declare is31 w/buffering preferred (low RAM will fall back on unbuffered)
+is31 = Adafruit_RGBMatrixQT(i2c, allocate=adafruit_is31fl3741.PREFER_BUFFER)
+#  In buffered mode, MUST use show() to refresh matrix (see line 94)
+
+#  brightness for the RGBMatrixQT
+#  set to about 20%
+is31.set_led_scaling(0x19)
+is31.global_current = 0x03
+is31.enable = True
+
+#  array of colors for the LEDs
+#  goes from purple to red
+#  gradient generated using https://colordesigner.io/gradient-generator
+heatmap = [0xb000ff,0xa600ff,0x9b00ff,0x8f00ff,0x8200ff,
+           0x7400ff,0x6500ff,0x5200ff,0x3900ff,0x0003ff,
+           0x0003ff,0x0047ff,0x0066ff,0x007eff,0x0093ff,
+           0x00a6ff,0x00b7ff,0x00c8ff,0x00d7ff,0x00e5ff,
+           0x00e0ff,0x00e6fd,0x00ecf6,0x00f2ea,0x00f6d7,
+           0x00fac0,0x00fca3,0x00fe81,0x00ff59,0x00ff16,
+           0x00ff16,0x45ff08,0x62ff00,0x78ff00,0x8bff00,
+           0x9bff00,0xaaff00,0xb8ff00,0xc5ff00,0xd1ff00,
+           0xedff00,0xf5eb00,0xfcd600,0xffc100,0xffab00,
+           0xff9500,0xff7c00,0xff6100,0xff4100,0xff0000,
+           0xff0000,0xff0000]
+
+#  size of the FFT data sample
+fft_size = 64
+
+#  setup for onboard mic
+mic = audiobusio.PDMIn(board.MICROPHONE_CLOCK, board.MICROPHONE_DATA,
+                       sample_rate=16000, bit_depth=16)
+
+#  use some extra sample to account for the mic startup
+samples_bit = array.array('H', [0] * (fft_size+3))
+
+#  sends visualized data to the RGB matrix with colors
+def waves(data, y):
+    offset = max(0, (13-len(data))//2)
+
+    for x in range(min(13, len(data))):
+        is31.pixel(x+offset, y, heatmap[int(data[x])])
+
+# main loop
+def main():
+    #  value for audio samples
+    max_all = 10
+    #  variable to move data along the matrix
+    scroll_offset = 0
+    #  setting the y axis value to equal the scroll_offset
+    y = scroll_offset
+
+    while True:
+        #  record the audio sample
+        mic.record(samples_bit, len(samples_bit))
+        #  send the sample to the ulab array
+        samples = np.array(samples_bit[3:])
+        #  creates a spectogram of the data
+        spectrogram1 = spectrogram(samples)
+        # spectrum() is always nonnegative, but add a tiny value
+        # to change any zeros to nonzero numbers
+        spectrogram1 = np.log(spectrogram1 + 1e-7)
+        spectrogram1 = spectrogram1[1:(fft_size//2)-1]
+        #  sets range of the spectrogram
+        min_curr = np.min(spectrogram1)
+        max_curr = np.max(spectrogram1)
+        #  resets values
+        if max_curr > max_all:
+            max_all = max_curr
+        else:
+            max_curr = max_curr-1
+        min_curr = max(min_curr, 3)
+        # stores spectrogram in data
+        data = (spectrogram1 - min_curr) * (51. / (max_all - min_curr))
+        # sets negative numbers to zero
+        data = data * np.array((data > 0))
+        #  resets y
+        y = scroll_offset
+        #  runs waves to write data to the LED's
+        waves(data, y)
+        #  updates scroll_offset to move data along matrix
+        scroll_offset = (y + 1) % 9
+        #  writes data to the RGB matrix
+        is31.show()
+
+main()