from machine import Pin, time_pulse_us
import time

trig_pin = Pin(16, Pin.OUT)  # D0 or GPIO-16 of NodeMCU
echo_pin = Pin(5, Pin.IN)    # D1 or GPIO-5 of NodeMCU

def measure_distance():
    trig_pin.off()  # Make trigPin low
    time.sleep_us(2)  # Wait for 2 microseconds
    trig_pin.on()  # Set trigPin high to start ultrasonic measurement
    time.sleep_us(10)  # Keep trigPin high for 10 microseconds
    trig_pin.off()  # Make trigPin low again

    duration = time_pulse_us(echo_pin, 1)  # Read echo pin to get the duration of the echo pulse in microseconds
    distance = duration * 0.034 / 2  # Calculate distance using the speed of sound (approximately 34,000 cm/s)
    return distance

# Main program
def main():
    trig_pin.init(Pin.OUT)
    echo_pin.init(Pin.IN)
    while True:
        distance = measure_distance()
        print("Distance = {} cm".format(distance))
        time.sleep(3)  # Pause for 3 seconds before starting the next measurement

if __name__ == "__main__":
    main()