ultra_distance.py

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)

GPIO_TRIGGER = 26
GPIO_ECHO = 6

GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
GPIO.setup(GPIO_ECHO, GPIO.IN)

def distance():
	GPIO.output(GPIO_TRIGGER,True)
	time.sleep(0.00001)
	GPIO.output(GPIO_TRIGGER, False)

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

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

	while GPIO.input(GPIO_ECHO) == 1:
		StopTime = time.time()

	TimeElapsed = StopTime - StartTime
	distance = (TimeElapsed * 34300) / 2

	return distance

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

	except KeyboardInterrupt:
		print("Measurement stopped")
		GPIO.cleanup()