A sample Python program to test the GPIO library

blink.py

from time import sleep
import RPi.GPIO as GPIO

# to use Raspberry Pi board pin numbers
GPIO.setmode(GPIO.BOARD)

# set up GPIO output channel
GPIO.setup(13, GPIO.OUT)
GPIO.setup(15, GPIO.OUT)
GPIO.setup(16, GPIO.OUT)

while 1:
    GPIO.output(13, GPIO.LOW)
    sleep(1)
    GPIO.output(13, GPIO.HIGH)
    sleep(1)

    GPIO.output(15, GPIO.LOW)
    sleep(1)
    GPIO.output(15, GPIO.HIGH)
    sleep(1)

    GPIO.output(16, GPIO.LOW)
    sleep(1)
    GPIO.output(16, GPIO.HIGH)
    sleep(1)