Control LED strip based on Serial input

button.py

import time
import serial
from neopixel import *

# LED strip configuration:
LED_COUNT      = 60      # Number of LED pixels.
LED_PIN        = 18      # GPIO pin connected to the pixels (must support PWM!).
LED_FREQ_HZ    = 800000  # LED signal frequency in hertz (usually 800khz)
LED_DMA        = 5       # DMA channel to use for generating signal (try 5)
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)

# Define functions which reads serial input.
def readline(port):
        received = ""
        while True:
                character = port.read()
                received += character
                if character=='\n':
                        return received

# Define function which animates LEDs.
def button(strip, r, g, b, wait_ms=0):
        """Button animation"""
        # Gradually light up
        for j in range(100):
                for i in range(strip.numPixels()):
                        strip.setPixelColor(i, Color(r*j/100, g*j/100, b*j/100))
                strip.show()
                time.sleep(wait_ms/1000.0)
        # Gradually light off
        for j in range(100):
                for i in range(strip.numPixels()):
                        strip.setPixelColor(i, Color(r*(100-j)/100, g*(100-j)/100, b*(100-j)/100))
                strip.show()
                time.sleep(wait_ms/1000.0)
        # Turn off
        for i in range(strip.numPixels()):
                strip.setPixelColor(i, Color(0, 0, 0))
                strip.show()
                
# Main program logic follows:
if __name__ == '__main__':
        # Create NeoPixel object with appropriate configuration.
        strip = Adafruit_NeoPixel(LED_COUNT, LED_PIN, LED_FREQ_HZ, LED_DMA, LED_INVERT, LED_BRIGHTNESS)
        # Intialize the library (must be called once before other functions).
        strip.begin()
        # Create serial port object with approoriate configuration.
        port = serial.Serial("/dev/ttyACM0", baudrate=115200)

        print 'Press Ctrl-C to quit.'
        while True:
                # Wait for serial input
                readline(port)
                # Then flash LEDs
                button(strip, 255, 255, 255)