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

medidor= HCSR04 (trigger_pin = 04, echo_pin= 5)
led = Pin(2)
while (True):
    try:
        distancia= medidor.distance_cm()
        print( "Distancia =", distancia, "cm" )
        if distancia >= 20:
            led. value(1)
            print("Encendido, alerta")
        else:
            led. value(0)
            print("No hay nadie, todo normal")
        sleep(1)
    except:
        print("Error")