from machine import Pin, time_pulse_us
import time

trig_pin = Pin(5, Pin.OUT) 
echo_pin = Pin(27, Pin.IN) 
while True:
    trig_pin.value(0)
    time.sleep_us(2)
    trig_pin.value(1)
    time.sleep_us(5)
    trig_pin.value(0)
    while echo_pin.value() == 0:
        time_off = time.ticks_us()
    while echo_pin.value() == 1:
        time_on = time.ticks_us()
    timelapsed = time_on-time_off
    distance = (timelapsed*0.343) / 2

    print("Distance : " ,distance , " cm")
    time.sleep_ms(500)