import machine 
import time 
import utime
from machine import Pin

TRIG = machine.Pin(7, machine.Pin.OUT)
ECHO = machine.Pin(8, machine.Pin.IN)
led = machine.Pin(5, Pin.OUT)


def distance():
    TRIG.low()
    time.sleep_us(2)
    TRIG.high()
    time.sleep_us(10)
    TRIG.low()

    while not ECHO.value():
        pass

    time1 = time.ticks_us()
    while ECHO.value():
        pass

    time2 = time.ticks_us() 
    during = time.ticks_diff(time2, time1)

    return during * 340 / 2 / 10000  


while True:
    dis = distance()
    print("Distance: %.2f cm" % dis)
    time.sleep_ms(300) 
    if dis <= 300:
        led.value(1)
    else:
        led.value(0)