import machine
import time

trig = machine.Pin(5, machine.Pin.OUT)
echo = machine.Pin(4, machine.Pin.IN)

while True:
    trig.value(0)
    time.sleep(0.0001)
    trig.value(1)

    while echo ==1:
        start = time.time()

    while echo ==0:
        end = time.time()

    sig_time = end-start

    distance = sig_time / 0.000148

    print( 'Distance: {} cm' .format(distance))
    return distance