import time
import board
import digitalio
import pulseio

TRIG_PIN = board.GP16
ECHO_PIN = board.GP17

# TRIG kimenet
trig = digitalio.DigitalInOut(TRIG_PIN)
trig.direction = digitalio.Direction.OUTPUT
trig.value = False

# PulseIn: mikrosekundumban méri a pulzusok hosszát
echo = pulseio.PulseIn(ECHO_PIN, maxlen=1, idle_state=False)

def measure_distance_cm(timeout_s=0.03) -> float:

    echo.clear()

    # TRIG impulzus az adatlap szerint: 10 µs HIGH
    trig.value = False
    time.sleep(0.000002)  # 2 µs "rendezés"
    trig.value = True
    time.sleep(0.000010)  # 10 µs
    trig.value = False

    t0 = time.monotonic()
    while len(echo) == 0:
        if time.monotonic() - t0 > timeout_s:
            raise RuntimeError("Timeout")

    pulse_us = echo.popleft()  # mikrosekundum

    cm = pulse_us * 0.01715
    return cm

while True:
    try:
        d = measure_distance_cm()
        print(f"Tavolsag: {d:6.1f} cm")
    except RuntimeError as e:
        print("Meresi hiba:", e)

    time.sleep(0.2)