Python code to light up a dragon's tail made of LEDs that attaches to the back of my bike.

test-dragon-tail.py

import time
import board
import neopixel
import random

# The number of NeoPixels
num_pixels = 240

# The order of the pixel colors - RGB or GRB. Some NeoPixels have red and green reversed!
# For RGBW NeoPixels, simply change the ORDER to RGBW or GRBW.
ORDER = neopixel.GRB

strip_one = neopixel.NeoPixel(
    board.D4, num_pixels, brightness=0.2, auto_write=False, pixel_order=ORDER
)

strip_two = neopixel.NeoPixel(
    board.D5, num_pixels, brightness=0.2, auto_write=False, pixel_order=ORDER
)

strip_three = neopixel.NeoPixel(
    board.D6, num_pixels, brightness=0.2, auto_write=False, pixel_order=ORDER
)

strip_four = neopixel.NeoPixel(
    board.D9, num_pixels, brightness=0.2, auto_write=False, pixel_order=ORDER
)

strip_five = neopixel.NeoPixel(
    board.D10, num_pixels, brightness=0.2, auto_write=False, pixel_order=ORDER
)

def fire_animation():
    while True:
        rgb = (255, 50, 12)
        delay = random.choice(range(10, 30))/1000
        for p in range(num_pixels):
            flicker = random.choice(range(40))
            rgb_r = tuple([x - flicker if x-flicker >= 0 else 0 for x in rgb ])
            pixels[p] = rgb_r
        pixels.show()
        time.sleep(delay)

def wheel(pos):
    # Input a value 0 to 255 to get a color value.
    # The colours are a transition r - g - b - back to r.
    if pos < 0 or pos > 255:
        r = g = b = 0
    elif pos < 85:
        r = int(pos * 3)
        g = int(255 - pos * 3)
        b = 0
    elif pos < 170:
        pos -= 85
        r = int(255 - pos * 3)
        g = 0
        b = int(pos * 3)
    else:
        pos -= 170
        r = 0
        g = int(pos * 3)
        b = int(255 - pos * 3)
    return (r, g, b) if ORDER in (neopixel.RGB, neopixel.GRB) else (r, g, b, 0)


def rainbow_cycle(wait):
    for j in range(255):
        for i in range(num_pixels):
            pixel_index = (i * 256 // num_pixels) + j
            strip_one[i] = wheel(pixel_index & 255)
        strip_one.show()
        for i in range(num_pixels):
            pixel_index = (i * 256 // num_pixels) + j
            strip_two[i] = wheel(pixel_index & 255)
        strip_two.show()
        for i in range(num_pixels):
            pixel_index = (i * 256 // num_pixels) + j
            strip_three[i] = wheel(pixel_index & 255)
        strip_three.show()
        for i in range(num_pixels):
            pixel_index = (i * 256 // num_pixels) + j
            strip_four[i] = wheel(pixel_index & 255)
        strip_four.show()
        for i in range(num_pixels):
            pixel_index = (i * 256 // num_pixels) + j
            strip_five[i] = wheel(pixel_index & 255)
        strip_five.show()
        #time.sleep(wait)

#fire_animation()
rainbow_cycle(0.001)
while True:
    rainbow_cycle(0.001)  # rainbow cycle with 1ms delay per step