led_strip.py

#!/usr/bin/python3

import time

from rpi_ws281x import *

# LED strip configuration:
LED_COUNT      = 12      # Number of LED pixels.
LED_PIN        = 12      # GPIO pin connected to the pixels (18 uses PWM!).
#LED_PIN        = 10      # GPIO pin connected to the pixels (10 uses SPI /dev/spidev0.0).
LED_FREQ_HZ    = 800000  # LED signal frequency in hertz (usually 800khz)
LED_DMA        = 10      # DMA channel to use for generating signal (try 10)
LED_BRIGHTNESS = 255     # Set to 0 for darkest and 255 for brightest
LED_INVERT     = False   # True to invert the signal (when using NPN transistor level shift)
LED_CHANNEL    = 0       # set to '1' for GPIOs 13, 19, 41, 45 or 53


def setup_led():
    # Create NeoPixel object with appropriate configuration.
    strip = Adafruit_NeoPixel(LED_COUNT, LED_PIN, LED_FREQ_HZ, LED_DMA, LED_INVERT, LED_BRIGHTNESS, LED_CHANNEL)

    # Intialize the library (must be called once before other functions).
    strip.begin()

    strip.setPixelColor(0, Color(255,255,0))
    strip.setPixelColor(1, Color(255,255,0))
    strip.setPixelColor(2, Color(255,255,0))
    strip.setPixelColor(3, Color(255,255,0))
    strip.setPixelColor(4, Color(255,255,0))
    strip.setPixelColor(5, Color(255,255,0))

    return strip                                    

def wheel(pos):
    """Generate rainbow colors across 0-255 positions."""
    if pos < 85:
        return Color(pos * 3, 255 - pos * 3, 0)
    elif pos < 170:
        pos -= 85
        return Color(255 - pos * 3, 0, pos * 3)
    else:
        pos -= 170
        return Color(0, pos * 3, 255 - pos * 3)

def rainbowCycle(strip, wait_ms=20, iterations=5):
    """Draw rainbow that uniformly distributes itself across all pixels."""
    for j in range(256*iterations):
            for i in range(strip.numPixels()):
                    strip.setPixelColor(i, wheel((int(i * 256 / strip.numPixels()) + j) & 255))
            strip.show()
            time.sleep(wait_ms/1000.0)

def theaterChaseRainbow(strip, wait_ms=50):
    """Rainbow movie theater light style chaser animation."""
    for j in range(256):
        for q in range(3):
            for i in range(0, strip.numPixels(), 3):
                strip.setPixelColor(i+q, wheel((i+j) % 255))
            strip.show()
            time.sleep(wait_ms/1000.0)
            for i in range(0, strip.numPixels(), 3):
                strip.setPixelColor(i+q, 0)


def colorWipe(strip, color):
    """Wipe color across display a pixel at a time."""
    for i in range(strip.numPixels()):
        strip.setPixelColor(i, color)
        strip.show()
        time.sleep(0.005)