from machine import Pin, time_pulse_us
from time import sleep

trig = Pin(15,Pin.OUT)
echo = Pin(14,Pin.IN)
LED = Pin(13,Pin.OUT)
button = Pin(12,Pin.IN,Pin.PULL_UP)
button.value() 

def set_distance():
    trig.low()
    sleep(0.002)
    trig.high()
    sleep(0.000001)
    trig.low()

    duration = time_pulse_us(echo,1)
    distance = (duration*0.0343)/2
    return distance

while True:
    while button.value() == 0:
        cm = set_distance()
        print("Distance: {}cm".format(cm))
        while not button.value() == 1:
            pass