aurora.py

#!/usr/bin/env python

import RPi.GPIO as GPIO
from time import *

GPIO.setmode(GPIO.BCM)
GPIO.setup(18, GPIO.OUT)
GPIO.setup(12, GPIO.OUT)
GPIO.setup(13, GPIO.OUT)

pwm =  GPIO.PWM(18, 500)
pwm2 = GPIO.PWM(12, 500)
pwm3 = GPIO.PWM(13, 500)
pwm.start(0)
pwm2.start(0)
pwm3.start(0)

while (True):
	for i in range(0, 100):
		pwm3.ChangeDutyCycle(i)
		sleep(0.01)
	for i in range(0, 100):
		pwm3.ChangeDutyCycle(100 - i)
		sleep(0.01)
	for i in range(0, 100):
		pwm2.ChangeDutyCycle(i)
		sleep(0.01)
	for i in range(0, 100):
		pwm2.ChangeDutyCycle(100 - i)
		sleep(0.01)
	for i in range(0, 100):
		pwm.ChangeDutyCycle(i)
		sleep(0.01)
	for i in range(0, 100):
		pwm.ChangeDutyCycle(100 - i)
		sleep(0.01)