import sys
import select
import os
import time
import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BOARD)
GPIO.setup(3, GPIO.OUT)

i = 0
while True:
     os.system('cls' if os.name == 'nt' else 'clear')
     print "I'm doing stuff. Press Enter to stop me!"
     print i
     GPIO.output(3, GPIO.HIGH)
     time.sleep(1)
     GPIO.output(3, GPIO.LOW)
     time.sleep(1)
     GPIO.output(3, GPIO.HIGH)
     time.sleep(1)
     GPIO.output(3, GPIO.LOW)
     time.sleep(1)
     if sys.stdin in select.select([sys.stdin], [], [], 0)[0]:
         line = raw_input()
         break
     i += 1