1  # SPDX-FileCopyrightText: 2018 Collin Cunningham for Adafruit Industries
 2  #
 3  # SPDX-License-Identifier: MIT
 4  
 5  import board
 6  from rainbowio import colorwheel
 7  import neopixel
 8  from analogio import AnalogIn
 9  
10  n_pixels = 10  # Number of pixels you are using
11  dc_offset = 0  # DC offset in mic signal - if unusure, leave 0
12  noise = 100  # Noise/hum/interference in mic signal
13  lvl = 10  # Current "dampened" audio level
14  maxbrt = 127  # Maximum brightness of the neopixels (0-255)
15  wheelStart = 0  # Start of the RGB spectrum we'll use
16  wheelEnd = 255  # End of the RGB spectrum we'll use
17  
18  mic_pin = AnalogIn(board.A7)
19  
20  # Set up NeoPixels and turn them all off.
21  strip = neopixel.NeoPixel(board.NEOPIXEL, n_pixels,
22                            brightness=0.1, auto_write=False)
23  strip.fill(0)
24  strip.show()
25  
26  
27  def remapRangeSafe(value, leftMin, leftMax, rightMin, rightMax):
28      # this remaps a value from original (left) range to new (right) range
29  
30      # Force the input value to within left min & max
31      if value < leftMin:
32          value = leftMin
33      if value > leftMax:
34          value = leftMax
35  
36      # Figure out how 'wide' each range is
37      leftSpan = leftMax - leftMin
38      rightSpan = rightMax - rightMin
39  
40      # Convert the left range into a 0-1 range (int)
41      valueScaled = int(value - leftMin) / int(leftSpan)
42  
43      # Convert the 0-1 range into a value in the right range.
44      return int(rightMin + (valueScaled * rightSpan))
45  
46  
47  while True:
48      n = int((mic_pin.value / 65536) * 1000)  # 10-bit ADC format
49      n = abs(n - 512 - dc_offset)  # Center on zero
50  
51      if n >= noise:  # Remove noise/hum
52          n = n - noise
53  
54      # "Dampened" reading (else looks twitchy) - divide by 8 (2^3)
55      lvl = int(((lvl * 7) + n) / 8)
56  
57      # Color pixels based on rainbow gradient
58      vlvl = remapRangeSafe(lvl, 0, 255, wheelStart, wheelEnd)
59      for i in range(0, len(strip)):
60          strip[i] = colorwheel(vlvl)
61          # Set strip brightness based oncode audio level
62          brightness = remapRangeSafe(lvl, 50, 255, 0, maxbrt)
63          strip.brightness = float(brightness) / 255.0
64      strip.show()