#!/usr/bin/python3

PIN_TRIGGER = 7
      ECHOS = [11, 13, 15]
      for e in ECHOS:
          GPIO.setup(e, GPIO.IN)

      GPIO.setup(PIN_TRIGGER, GPIO.OUT)


      GPIO.output(PIN_TRIGGER, GPIO.LOW)

      print ("Waiting for sensor to settle")

      time.sleep(2)

      print ("Calculating distance")

      GPIO.output(PIN_TRIGGER, GPIO.HIGH)

      time.sleep(0.00001)

      GPIO.output(PIN_TRIGGER, GPIO.LOW)

      while GPIO.input(e) == 0:
            pulse_start_time = time.time()
      while GPIO.input(e) == 1:
            pulse_end_time = time.time()

      pulse_duration = pulse_end_time - pulse_start_time
      distance = round(pulse_duration * 17150, 2)
      if distance < 30:
          print("Object close")
      #print ("Distance:",distance,"cm")