import time
from machine import Pin

# Ultrasonic pins
trigger = Pin(3, Pin.OUT)
echo = Pin(2, Pin.IN)

# LED pin
led = Pin(14, Pin.OUT)

def get_distance():
    # Send trigger pulse
    trigger.low()
    time.sleep_us(2)
    trigger.high()
    time.sleep_us(10)
    trigger.low()

    # Measure echo time
    while echo.value() == 0:
        signal_off = time.ticks_us()

    while echo.value() == 1:
        signal_on = time.ticks_us()

    # Time difference
    time_passed = time.ticks_diff(signal_on, signal_off)

    # Convert to distance (cm)
    distance = (time_passed * 0.0343) / 2

    return distance

print("Ultrasonic Distance Detection Ready...")

while True:
    distance = get_distance()
    print("Distance:", distance, "cm")

    # 5 meters = 500 cm
    if distance <= 50:
        led.value(1)  # Object detected → LED ON
    else:
        led.value(0)  # No object → LED OFF

    time.sleep(0.2)