import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM) # GPIO Numbers instead of board numbers
RELAIS_1_GPIO = 27
GPIO.setup(RELAIS_1_GPIO, GPIO.OUT) # GPIO Assign mode

# here you would put all your code for setting up GPIO,  
# we'll cover that tomorrow  
# initial values of variables etc...  
counter = 0  
  
try:  
    # here you put your main loop or block of code  
    while True:  
        # count up to 9000000 - takes ~20s
        time.sleep(3)
        print ("Hellooooo")
        if counter % 2 ==0: 
            GPIO.output(RELAIS_1_GPIO, GPIO.LOW) # out
        else:
            GPIO.output(RELAIS_1_GPIO, GPIO.HIGH) # out
        
        counter += 1  
    print ("Target reached: %d" % counter)  
  
except KeyboardInterrupt:  
    # here you put any code you want to run before the program   
    # exits when you press CTRL+C  
    print ("\n", counter) # print value of counter  
  
except:  
    # this catches ALL other exceptions including errors.  
    # You won't get any error messages for debugging  
    # so only use it once your code is working  
    print ("Other error or exception occurred!")  
  
finally:  
    GPIO.cleanup() # this ensures a clean exit