Raspberry Pi Lesson: Ultrasonic HC-SR04

Raspberry Pi Ultrasonic HC-SR04

import RPi.GPIO as GPIO
import time

TRIG = 24
ECHO = 23

GPIO.setmode(GPIO.BCM)
GPIO.setup(TRIG,GPIO.OUT)
GPIO.setup(ECHO,GPIO.IN)

while 1:
    time.sleep(1)

    GPIO.output(TRIG,True)
    time.sleep(0.00001)
    GPIO.output(TRIG,False)

    while GPIO.input(ECHO)==0:
        pulse_start = time.time()

    while GPIO.input(ECHO)==1:
        pulse_end = time.time()

    pulse_duration = pulse_end - pulse_start

    distance = pulse_duration * 17150
    distance = round(distance,2)

    print "Distance = " + str(distance) + "cm"