Micropython NeoPixel LED strip lighting effect for beat drops

beat_drop.py

# A short sequence of LED flashes that doubles in frequency with each repetition, ending with a strobe.

import machine, neopixel
from time import ticks_ms, sleep_ms

bpm = 134       # 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

np = neopixel.NeoPixel(machine.Pin(data_pin), num_leds)

trigger = 1  # ideally, this would be triggered by an input rather than hard coded

while (trigger > 0):
    for i in range(0, 3):  # cycle through the four colors
      multiplier = 2 ** i  # used to double the frequency with each repetition
      for j in range(0, multiplier):   
        start_time = ticks_ms()  # used to calculate execution time of LED chase sequence
        np.fill((64, 0, 0))  # red
        np.write()
        delay = round(60 / bpm * 1000)  # 60 sec / bpm * 1000 gives milliseconds between beats
        delay = round(delay / multiplier)
        execution_time = ticks_ms() - start_time  # figure out how much time was spent in chase sequence
        delay = round(delay - execution_time)  # subtract time spent calculating for better synchronization
        sleep_ms(delay)

        np.fill((0, 64, 0))  # green
        np.write()
        sleep_ms(delay)

        np.fill((0, 32, 32))  # blue (azure)
        np.write()
        sleep_ms(delay)

        np.fill((32, 0, 32))  # violet
        np.write()
        sleep_ms(delay)

    # Finish with a strobe effect.
    delay = delay >> 1  # a fast way to divide by two
    for i in range(1, 16):
        np.fill((255, 255, 255))
        np.write()
        sleep_ms(1)
        np.fill((0, 0, 0))
        np.write()
        sleep_ms(delay)

    trigger = 0