led.py

import RPi.GPIO as GPIO
import time

Led = 11   # pin11

def setup():
    GPIO.setmode(GPIO.BOARD)          # Numbering according to the physical location
    GPIO.setup(Led, GPIO.OUT)         # Set pin mode as output
    GPIO.output(Led, GPIO.HIGH)       # Output high level(+3.3V) to off the led

def loop():
    while True:
        print "...led on"
        GPIO.output(Led, GPIO.LOW)    # led on
        time.sleep(1.0)
        print "led off..."
        GPIO.output(Led, GPIO.HIGH)   # led off
        time.sleep(0.5)

def destroy():
    GPIO.output(Led, GPIO.HIGH)       # led off
    GPIO.cleanup()                    # Release resource

if __name__ == '__main__':            # Program start from here
    setup()
    try:
        loop()
    except KeyboardInterrupt:         # Press 'Ctrl+C' to end the program
        destroy()