KCPWMLED

#!/usr/bin/env python2.7
# script by Sparks N Smoke for SOFTWARE control of LEDs with Pulse Width Modulation

import RPi.GPIO as GPIO
from time import sleep
GPIO.setmode(GPIO.BCM)

GPIO.setup(24, GPIO.OUT)                                 # LED Red PWM port - can use any GPIO port !
GPIO.setup(25, GPIO.OUT)                                 # LED Green PWM port
GPIO.setup(26, GPIO.OUT)                                 # LED Blue PWM port

frequency = 40                                           # set the LED pulse cycle frequency (40 Hertz)
delay = 0.02                                             # set no of secs to wait on duty cycle change

Red = GPIO.PWM(24, frequency)                            # set port 24 to 40 Hertz
Green = GPIO.PWM(25, frequency)                          # set port 13 to 40 Hertz
Blue = GPIO.PWM(26, frequency)                           # set port 18 to 40 Hertz

Red.start(0)                                             # start with 0% duty cycle
Green.start(0)                                           
Blue.start(0)

try:
    while True:
        for i in range (0, 101, 1):                      # 100 is the last value executed
            Red.ChangeDutyCycle(i)                       # change duty cycle to the value of i (going UP)
            sleep(delay)                                 # linger a while at each step with RED
        for i in range (100, -1, -1):                    # 0 is the last value executed
            Red.ChangeDutyCycle(i)                       # value of duty cycle going DOWN
            sleep(delay)
        sleep(delay*5)                                   # linger a bit longer with the LED off completely
   
        for i in range (0, 101, 1):                      # now deal with GREEN
            Green.ChangeDutyCycle(i)
            sleep(delay)
        for i in range (100, -1, -1):
            Green.ChangeDutyCycle(i)
            sleep(delay)
        sleep(delay*5)

        for i in range (0, 101, 1):                      # now deal with BLUE
            Blue.ChangeDutyCycle(i)
            sleep(delay)
        for i in range (100, -1, -1):
            Blue.ChangeDutyCycle(i)
            sleep(delay)
        sleep(delay*5)

except KeyboardInterrupt:
    print " CTRL-C detected"
    Red.stop()
    Green.stop()
    Blue.stop()
    GPIO.cleanup()                                       # Reset ports on CTRL-C