sonar.py

import RPi.GPIO as GPIO
import time

#set GPIO Pins
GPIO_TRIGGER = 25 
GPIO_ECHO = 22

class Sonar():

    def __init__(self):
        #GPIO Mode (BOARD / BCM)
        GPIO.setmode(GPIO.BCM)
        
        #set GPIO direction (IN / OUT)
        GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
        GPIO.setup(GPIO_ECHO, GPIO.IN)
    
    def distance(self):
        # 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
        #GPIO.cleanup()
        return distance