import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM)
GPIO.setup(4,GPIO.OUT)
try:
	while True:
		GPIO.output(4,True)
		time.sleep(0.5)
		GPIO.output(4,False)
		time.sleep(0.5)
		print("blink")
except KeyboardInterrupt :
	GPIO.cleanup()

