from machine import Pin
from neopixel import NeoPixel
from time import sleep

pixel_pin  = 22
num_pixels = 16
pixels = NeoPixel(Pin(pixel_pin ), num_pixels)


def wheel(pos):

    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)


def rainbow_cycle(wait):
    for j in range(0,256,8):
        for i in range(num_pixels):
            pixel_index = (i * 256 // num_pixels) + j
            pixels[i] = wheel(pixel_index & 255)
        pixels.write()
        sleep(wait)


while True:
    pixels.fill((255, 0, 0)); pixels.write(); sleep(1)

    pixels.fill((0, 255, 0)); pixels.write(); sleep(1)

    pixels.fill((0, 0, 255)); pixels.write(); sleep(1)

    rainbow_cycle(0.001)  # rainbow cycle with 1ms delay per step