from hcsr04 import HCSR04 
import machine
from machine import Pin
from time import sleep

led = Pin(2,Pin.OUT)


sensor = HCSR04(trigger_pin=12, echo_pin=14,echo_timeout_us=10000)

while True:
    distance = sensor.distance_cm()
    print('distance:',distance,'cm')
    if distance<50:
        led.on()
    else:
        led.off()
    sleep(1)