Simple Python 3 test of the HC-SR04 module on Raspberry Pi

HCSR04.py

import RPi.GPIO as GPIO
from time import sleep, time

# RPi Setup stuff
GPIO.setmode(GPIO.BCM)
trig = 23
echo = 24
GPIO.setup(trig, GPIO.OUT)
GPIO.setup(echo, GPIO.IN)
GPIO.output(trig, False)
sleep(1)  # let the system and sensor settle

while True:  # Loop forever
    GPIO.output(trig, True)
    sleep(0.00001)  # keep pin high for 10 uS
    GPIO.output(trig, False)
    # Wait for the incoming pulse
    while GPIO.input(echo) == 0:
        pulse_start = time()
    # Wait for the end ofthe pulse
    while GPIO.input(echo) == 1:
        pulse_end = time()
    # Measure the width of the pulse base on python's timing
    pulse_duration = pulse_end - pulse_start
    dist_cm = pulse_duration / 58
    dist_in = pulse_duration / 148
    print(("Distance in centimeters: ", dist_cm))
    print(("Distance in inches: ", dist_in))
    sleep(0.05)  # Let the sound dissipate