from machine import Pin
import utime

# Pin Definitions
TRIG = Pin(3, Pin.OUT)
ECHO = Pin(2, Pin.IN)

def measure_distance():
    # Send 10us pulse to trigger
    TRIG.low()
    utime.sleep_us(2)
    TRIG.high()
    utime.sleep_us(10)
    TRIG.low()

    # Wait for echo to go high
    while ECHO.value() == 0:
        pulse_start = utime.ticks_us()

    # Wait for echo to go low
    while ECHO.value() == 1:
        pulse_end = utime.ticks_us()

    # Time difference
    duration = pulse_end - pulse_start
    # Speed of sound = 343 m/s or 0.0343 cm/us
    distance = (duration * 0.0343) / 2
    return distance

# Main Loop
while True:
    dist = measure_distance()
    print("Distance:", dist, "cm")
    utime.sleep(1)