from machine import Pin
import time
trig=Pin(18,Pin.OUT)
echo=Pin(19,Pin.IN)
while True:
    trig.off()
    time.sleep_us(2)
    trig.on()
    time.sleep_us(2)
    trig.off()
    while echo.value()==0:
        siga=time.ticks_us()
    while echo.value()==1:
        sigb=time.ticks_us()
    tm=sigb-siga
    d=(tm*.0343)/2
    print(d)
    time.sleep(1)