Moving rainbow on built-in board.NEOPIXEL
In CircuitPython 7, the rainbowio module has a colorwheel() function. Unfortunately, the rainbowio module is not available in all builds. In CircuitPython 6, colorwheel() is a built-in function part of _pixelbuf or adafruit_pypixelbuf.
Documentation on rainbowio is here.
The colorwheel() function takes a single value 0-255 hue and returns an (R,G,B) tuple given a single 0-255 hue. It's not a full HSV_to_RGB() function but often all you need is "hue to RGB", where you assume saturation=255 and value=255. It can be used with neopixel, adafruit_dotstar, or any place you need a (R,G,B) 3-byte tuple. Here's one way to use it.
# CircuitPython 7 with or without rainbowio module
import time, board, neopixel
try:
from rainbowio import colorwheel
except:
def colorwheel(pos):
if pos < 0 or pos > 255: return (0, 0, 0)
if pos < 85: return (255 - pos * 3, pos * 3, 0)
if pos < 170: pos -= 85; return (0, 255 - pos * 3, pos * 3)
pos -= 170; return (pos * 3, 0, 255 - pos * 3)
led = neopixel.NeoPixel(board.NEOPIXEL, 1, brightness=0.4)
while True:
led.fill( colorwheel((time.monotonic()*50)%255) )
time.sleep(0.05)
# CircuitPython 6 import time import board import neopixel led = neopixel.NeoPixel(board.NEOPIXEL, 1, brightness=0.4) while True: led.fill( neopixel._pixelbuf.colorwheel((time.monotonic()*50)%255) ) time.sleep(0.05)
import time, random
import board, neopixel, rainbowio
num_leds = 16
leds = neopixel.NeoPixel(board.D2, num_leds, brightness=0.4, auto_write=False )
delta_hue = 256//num_leds
speed = 10 # higher numbers = faster rainbow spinning
i=0
while True:
for l in range(len(leds)):
leds[l] = rainbowio.colorwheel( int(i*speed + l * delta_hue) % 255 )
leds.show() # only write to LEDs after updating them all
i = (i+1) % 255
time.sleep(0.05)
import time, random import board, neopixel num_leds = 16 leds = neopixel.NeoPixel(board.D2, num_leds, brightness=0.4, auto_write=False ) my_color = (55,200,230) dim_by = 20 # dim amount, higher = shorter tails pos = 0 while True: leds[pos] = my_color leds[0:] = [[max(i-dim_by,0) for i in l] for l in leds] # dim all by (dim_by,dim_by,dim_by) pos = (pos+1) % num_leds # move to next position leds.show() # only write to LEDs after updating them all time.sleep(0.05)
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