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

trig = Pin(27,Pin.OUT)
echo = Pin(26,Pin.IN)
led  = Pin(25,Pin.OUT)
led.value(0)
distance = 0 
derniere_distance=0

def callback_timer(t) : 
    led.value(not(led.value()))

tim0 = Timer(0) 
tim0.init(period=500, mode=Timer.PERIODIC, callback=callback_timer)



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)


def miseAjourTimer(distance):
    global derniere_distance

    if abs(distance-derniere_distance) >2 : 
        derniere_distance = distance
        frequence = (distance * 10)
        print(frequence)
        if frequence > 3000 : 
            tim0.deinit()
        else : 
            tim0.deinit()
            tim0.init(period=int(frequence), mode=Timer.PERIODIC, callback=callback_timer)
    
while True : 
    d= mesureHCSR04()
    
    if  d>=50 : 
        print(f"--.--")
    else : 
        print(f"{d}CM")

    miseAjourTimer(d)

    sleep_ms(200)