Datasheet

When declaring a NeoPixel object in CircuitPython, the object's argument list requires the output pin you'll use and the

number of pixels. There's two optional arguments, brightness (range from 0 (off) to 1.0 (full brightness)) and auto_write .

When auto_write is set to True , every pixel change is immediately written to the strip…this is easier to use but

way

slower. If you set auto_write=False then you will have to call strip.show() when you want to actually write color data out.

You can easily set colors by indexing into the location strip[n] = (red, green, blue) . For example, strip[0] = (100, 0, 0) will

set the first pixel to a medium-brightness red, and strip[2] = (0, 255, 0) will set the third pixel to bright green. Then, if you

have auto_write=False don't forget to call strip.show() .

# CircuitPython demo - NeoPixel

import board

import neopixel

import time

pixpin = board.D1

numpix = 10

strip = neopixel.NeoPixel(pixpin, numpix, brightness=0.3, auto_write=False)

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):

return (0, 0, 0)

if (pos < 85):

return (int(pos * 3), int(255 - (pos*3)), 0)

elif (pos < 170):

pos -= 85

return (int(255 - pos*3), 0, int(pos*3))

else:

pos -= 170

return (0, int(pos*3), int(255 - pos*3))

def rainbow_cycle(wait):

for j in range(255):

for i in range(len(strip)):

idx = int ((i * 256 / len(strip)) + j)

strip[i] = wheel(idx & 255)

strip.write()

time.sleep(wait)

while True:

strip.fill((255, 0, 0))

strip.write()

time.sleep(1)

strip.fill((0, 255, 0))

strip.write()

time.sleep(1)

strip.fill((0, 0, 255))

strip.write()

time.sleep(1)

rainbow_cycle(0.001) # rainbowcycle with 1ms delay per step