====== Capteurs ultrasonore ======

===== Mesure de distance =====
   def distance:
      from __future__ import print_function
      import time
      import RPi.GPIO as GPIO
      def measure():
        GPIO.output(GPIO_TRIGGER, True)
        time.sleep(0.00001)
        GPIO.output(GPIO_TRIGGER, False)
        start = time.time()
        while GPIO.input(GPIO_ECHO)==0:
          start = time.time()
        while GPIO.input(GPIO_ECHO)==1:
          stop = time.time()
        elapsed = stop-start
        distance = (elapsed * speedSound)/2
        return distance
      def measure_average():
        distance1=measure()
        time.sleep(0.1)
        distance2=measure()
        time.sleep(0.1)
        distance3=measure()
        distance = (distance1 + distance2 + distance3)/3
        return distance
        GPIO.setmode(GPIO.BCM)
      GPIO_TRIGGER = 23
      GPIO_ECHO    = 24
      temperature = 20
      speedSound = 33100 + (0.6*temperature)
      print("Ultrasonic Measurement")
      print("Speed of sound is",speedSound/100,"m/s at ",temperature,"deg")
      GPIO.setup(GPIO_TRIGGER,GPIO.OUT)  # Trigger
      GPIO.setup(GPIO_ECHO,GPIO.IN)      # Echo
      GPIO.output(GPIO_TRIGGER, False)
      time.sleep(0.5)
      try:
        while True:
          distance = measure_average()
          print("Distance : {0:5.1f}".format(distance))
          time.sleep(1)
      except KeyboardInterrupt:
        GPIO.cleanup()

==== Test arrêt d'urgence ====


===== Documentation =====

https://www.domo-blog.fr/capteur-de-distance-sur-raspberry/

====== Retour=====
  *   [[isn:2017:projetmariokart:accueil|Projet Mariokart]]