from machine import Pin, time_pulse_us
from time import sleep_us, sleep

# === CONFIGURATION ===
TRIGGER_PIN = 26
ECHO_PIN = 25
MAX_DISTANCE_CM = 500
ECHO_TIMEOUT_US = MAX_DISTANCE_CM * 2 / 0.0343  # time for max range

# === SETUP PINS (initialized once) ===
trigger = Pin(TRIGGER_PIN, Pin.OUT)
echo = Pin(ECHO_PIN, Pin.IN)

def check_distance():
    trigger.value(0)
    sleep_us(2)
    # Send 10µs pulse
    trigger.value(1)
    sleep_us(10)
    trigger.value(0)

    pulse_time = time_pulse_us(echo, 1, int(ECHO_TIMEOUT_US))
    return pulse_time
 
def distance_cm():
    pulse_time = check_distance()
    distance = (pulse_time / 2) * 0.0343
    if distance < 2 : 
       distance = 0 
    return distance

while True:
    d_cm = distance_cm()
    print("Distance: ", d_cm, "cm")
    sleep(0.5)