Micropython NeoPixel LED strip DJ lighting effect

dance_the_rainbow.py

# LED chase that pulses to the beat of the music and features a color changing background.

import machine, neopixel
from time import ticks_ms, sleep_ms

bpm = 128       # Tempo of your mix in beats per minute
num_leds = 42   # Number of NeoPixel LEDs in the strip
data_pin = 16   # Data pin for the NeoPixel strip
bg_colors = [   # Series of changing background colors
    (16, 0, 0), # red
    (12, 4, 0), # orange
    (9, 7, 0),  # yellow
    (0, 16, 0), # green
    (0, 4, 12), # blue
    (6, 0, 10), # violet
]

np = neopixel.NeoPixel(machine.Pin(data_pin), num_leds)
np.fill(bg_colors[0])
np.write()

bg_index = 0
for j in range(1, 8 * len(bg_colors) + 1):  # run through the sequence for 8 beats
    start_time = ticks_ms()  # used to calculate execution time of LED chase sequence
    
    for i in range(0, num_leds):  # send a bright white pixel down the line of LEDs
        np[i] = (255, 255, 255)
        if (i > 0):
            np[i - 1] = bg_colors[bg_index]
        np.write()
        sleep_ms(1)
    np[num_leds - 1] = bg_colors[bg_index]  # turn off the last LED after a sequence
    np.write()

    if (j % 8 == 0):  # change the background color after every 8 beats
        bg_index += 1
        if (bg_index >= len(bg_colors)):
            bg_index = 0
        
    delay = round(60 / bpm * 1000)  # 60 sec / bpm * 1000 gives milliseconds between beats 
    execution_time = ticks_ms() - start_time  # figure out how much time was spent in chase sequence
    delay -= execution_time  # subtract execution time from time between beats for better synchronization
    sleep_ms(delay)

np.fill((0,0,0))
np.write()