Neopixels (Part 7)

  2 minute read  

Let’s setup a list of colours for the other two lights to cycle through. We’ll also set up a variable that reminds us where in the cycle of colours we’re up to (like you might use your finger to keep track of which line you’re on when reading).

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import board
import time
import neopixel
from touchio import TouchIn

touch = TouchIn(board.A2)

# LED strip
pixels = neopixel.NeoPixel(board.D1, 3, brightness=1,
    auto_write=True, pixel_order=neopixel.GRBW)

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):
        return [0, 0, 0]
    if (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)]

colors = [
    (255, 0, 0, 0),
    (255, 255, 0, 0),
    (0, 255, 0, 0),
    (0, 255, 255, 0),
    (0, 0, 255, 0),
    (255, 0, 255, 0),
    (255, 255, 255, 0),
    (0, 0, 0, 255),
    (0, 0, 0, 0)
]
colorIndex = 0
pressTime = 0
on = False
i = 0
while True:
    if touch.value and pressTime == 0:
        pressTime = time.monotonic()
    
    if not touch.value and pressTime != 0:
        holdTime = time.monotonic()-pressTime
        pressTime = 0
        if holdTime > 1:
            on = not on
        else:
            colorIndex = (colorIndex+1) % len(colors)
    
    if on:
        pixels[0] = wheel(i)
        pixels[1] = colors[colorIndex]
        pixels[2] = colors[colorIndex]
    else:
        pixels.fill((0, 0, 0, 0))
    
    i = (i+1) % 256