import RPi.GPIO as GPIO             #importing the RPi.GPIO module
import time                        #importing the time module
GPIO.cleanup()                     #to clean up at the end of your script
led_pin = 37                       #select the pin for the LED
motion_pin = 35                    #select the pin for the motion sensor
def init():
  GPIO.setmode(GPIO.BOARD)         #to specify which pin numbering system
  GPIO.setwarnings(False)
  GPIO.setup(led_pin,GPIO.OUT)                             #declare the led_pin as an output
  GPIO.setup(motion_pin,GPIO.IN,pull_up_down=GPIO.PUD_UP)  #declare the motion_pin as an input
  print("-----------------------------------------------------------------------")

def main():
  while True:
    value=GPIO.input(motion_pin)
    if value!=0:                             #to read the value of a GPIO pin
      GPIO.output(led_pin,GPIO.HIGH)                #turn on led
      time.sleep(2)        #delay 2ms
      print "LED on"                           #print information
    else:
      GPIO.output(led_pin,GPIO.LOW)                #turn off led
      time.sleep(2)       #delay 2ms
      print "LED off"                         #print information

init()
main()
GPIO.cleanup()