from machine import Pin 
import time 
trig = Pin(14 , Pin.OUT)
echo = Pin(17 , Pin.IN)
Ton = Toff = 0
while 1 :
    trig.on()
    time.sleep_us(10)
    trig.off()

    while echo.value()==0:
        Toff = time.ticks_us()
    while echo.value()==1:
        Ton = time.ticks_us()
    t = (Ton-Toff) / 2 
    distance = 0.034 * t 
    print(distance)
    time.sleep_ms(40)