RGB灯

robotbit扩展板4个rgb灯，r-红，g-绿，b-蓝，值为0~255，可模拟出256*256*256种颜色。

from microbit import *

import neopixel
r = 0
g = 0
b = 0
np = neopixel.NeoPixel(pin16, 4)
for r in range(0,256,10):
    for g in range(0,256,10):
        for b in range(0,256,10):
            np[0] = (r, g, b)
            sleep(200)
            np.show()

函数 neopixel.NeoPixel(PIN, NUM) 用来创建 neopixel 对象，它有两个参数，第一个是GPIO，第二个是彩灯的数量。

neopixel 对象是一个元组列表，每个列表项都是由 RGB 三种颜色组成的元组。RGB参数的范围是 0-255，三种颜色组合起来就有 256 x 256 x 256 = 1.67M种颜色。

颜色参数写入列表后并不能改变彩灯，还需要调用函数 show()，才会更新。如果要清除彩灯，可以调用函数 clear().

官方的例子，随机显示彩灯。

"""
    neopixel_random.py

    Repeatedly displays random colours onto the LED strip.
    This example requires a strip of 8 Neopixels (WS2812) connected to pin0.

"""
from microbit import *
import neopixel
from random import randint

# Setup the Neopixel strip on pin0 with a length of 8 pixels
np = neopixel.NeoPixel(pin16, 4)

while True:
    #Iterate over each LED in the strip

    for pixel_id in range(0, len(np)):
        red = randint(0, 60)
        green = randint(0, 60)
        blue = randint(0, 60)

        # Assign the current LED a random red, green and blue value between 0 and 60
        np[pixel_id] = (red, green, blue)

        # Display the current pixel data on the Neopixel strip
        np.show()
        sleep(500)