HC-SR04 Sensor

# works with sonic sensor HC-SR04

from gpiozero import DistanceSensor
from time import sleep

import sys

sensor = DistanceSensor(echo=17, trigger=4, max_distance=2, threshold_distance=0.04)    #defines min and max in meters
sys.stdout.flush()

try:
    while True:
        pingerValue = float(sensor.distance * 100)  # convert snsor reading to cm
        if pingerValue <= 4.00 :                    # min distance to read is 4cm
            sys.stdout.write("\rDistance: >>>...")  # using sys.stdout write in place of print as it give neater terminal output
        elif pingerValue >= 200.00 :                # max distance to read is 200cm. NB: To test keep the distance at less than 100cm.
            sys.stdout.write("\rDistance: <<<...")
        elif sys.stdout.write("\rDistance: %6.2f" % pingerValue + " cm\r") : # \r for terminal; \n for IDLE window
            sys.stdout.flush()                      # clear screen
            sleep(0.01)

except KeyboardInterrupt:

    print ("\nExit")
    sys.stdout.flush()