from machine import Pin
import time
trig = Pin(17, Pin.OUT)
echo = Pin(16, Pin.IN, Pin.PULL_DOWN)

pin_0 = Pin(0,Pin.OUT) 
pin_1 = Pin(1,Pin.OUT)
pin_2 = Pin(2,Pin.OUT)

while True:
    trig.value(0)
    time.sleep(0.1)
    trig.value(1)
    time.sleep_us(2)
    trig.value(0)
    while echo.value()==0:
        pulse_start = time.ticks_us()
    while echo.value()==1:
        pulse_end = time.ticks_us()
    pulse_duration = pulse_end - pulse_start
    distance = pulse_duration * 17165 / 1000000
    distance = int(round(distance, 0))
    print ('Distance:',"{:.0f}".format(distance),'cm')
    time.sleep(1)
    length = str(distance) 
    pin_0.value(int(length[0]) % 2 == 0)
    pin_1.value(int(length[1]) % 2 == 0)
    pin_2.value(int(length[2]) % 2 == 0)