from machine import Pin, 
from time import sleep_us,sleep_ms,sleep,ticks_us,ticks_diff
import time

trig = Pin(27,Pin.OUT)
echo = Pin(26,Pin.IN)
distance = 0 
def mesureHCSR04():
    global distance
    t1=0
    t0=0
    trig.value(0)
    sleep_us(20)
    trig.value(1)
    sleep_us(10)
    trig.value(0)
    while echo.value()==0:
        pass
    t0 = time.ticks_us()
    while echo.value()==1:
        pass
    t1 = time.ticks_us()
    
    distance = time.ticks_diff(t1,t0)
    distance = (distance * 340 *1e-4)/2

    return round(distance,0)

while True : 
    d= mesureHCSR04()
    
    if  d>=50 : 
        print(f"--.--")
    else : 
        print(f"{d}CM")

    sleep(2)