import time
from machine import Pin

# HC-SR04 Pin Definetion 
trig = Pin(15, Pin.OUT)
echo = Pin(2, Pin.IN)

# Buzzer Pin Definetion
buzzer = Pin(18, Pin.OUT)

# Led Pin Definetion
led = Pin(4, Pin.OUT)

# Function To Measure Distance Using HC-SR04
def measure_distance():
    trig.value(0)
    time.sleep(0.000002)
    trig.value(1)
    time.sleep(0.00001)
    trig.value(0)

    timeout = 10000
    count = 0

    while echo.value() == 0 and count < timeout:
        count += 1
    start = time.ticks_us()

    count = 0
    while echo.value() == 1 and count < timeout:
        count += 1
    end = time.ticks_us()

    duration = end - start
    distance = (duration * 0.0343) / 2
    return distance

while True:
    try:
        d = measure_distance()
        print("Distance:", d, "cm")

        if d < 200:
            buzzer.value(1)
            led.value(1)

        else:
            buzzer.value(0)
            led.value(0)

    except Exception as e:
        print("❌ Error:", e)
        buzzer.value(0)
        led.value(0)

    time.sleep(0.5)