Ultrasonisk Sensor

#Libraries
import RPi.GPIO as GPIO
import time

#GPIO Mode (BOARD / BCM)
GPIO.setmode(GPIO.BCM)

#set GPIO Pins
GPIO_TRIGGER = 18
GPIO_ECHO = 24

#set GPIO direction (IN / OUT)
GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
GPIO.setup(GPIO_ECHO, GPIO.IN)

def distance():
   # set Trigger to HIGH
   GPIO.output(GPIO_TRIGGER, True)

   # set Trigger after 0.01ms to LOW
   time.sleep(0.00001)
   GPIO.output(GPIO_TRIGGER, False)

   StartTime = time.time()
   StopTime = time.time()

   # save StartTime
   while GPIO.input(GPIO_ECHO) == 0:
   StartTime = time.time()

# save time of arrival
while GPIO.input(GPIO_ECHO) == 1:
StopTime = time.time()

   # time difference between start and arrival
   TimeElapsed = StopTime - StartTime
   # multiply with the sonic speed (34300 cm/s)
   # and divide by 2, because there and back
   distance = (TimeElapsed * 34300) / 2

   return distance

if __name__ == '__main__':
   try:
      while True:
         dist = distance()
         print ("Measured Distance = %.1f cm" % dist)
         time.sleep(1)

   # Reset by pressing CTRL + C
except KeyboardInterrupt:
   print("Measurement stopped by User")
   GPIO.cleanup()