led_strip.py

# Simple test for NeoPixels on Raspberry Pi
import threading
import board
import neopixel
import colorsys
from random import randint

def hsv2rgb(h,s,v):
        return tuple(round(i * 255) for i in colorsys.hsv_to_rgb(h,s,v))

# Choose an open pin connected to the Data In of the NeoPixel strip, i.e. board.D18
# NeoPixels must be connected to D10, D12, D18 or D21 to work.
pixel_pin = board.D18

# The number of NeoPixels
num_pixels = 300

# 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.RGB

pixels = neopixel.NeoPixel(
    pixel_pin, num_pixels, brightness=0.2, auto_write=False
)


black = (0,0,0)
pixels.fill(black)
hue = 0
pixels.show()

def fadeToBlackBy(pixel, multiplier):
    return ( int(pixel[0] * multiplier), int(pixel[1] * multiplier), int(pixel[2] * multiplier) )

def confetti():
    # fade
    for position in range(num_pixels):
        pixel = pixels[position]
        pixels[position] = fadeToBlackBy(pixels[position], .95)

    pos = randint(0, num_pixels-1)
    color = hsv2rgb( (int(randint(0, 65) + hue)) % 360 / 360,  200/255, 255/255 )
    pixels[pos] = color

    pixels.show()

def increment_hue():
    global hue
    threading.Timer(.02, increment_hue).start()
    hue = hue + 1

increment_hue()
while True:
    confetti()