from machine import Pin, Timer
import utime

timer=Timer()
trigger=Pin(3,Pin.OUT)
echo=Pin(2,Pin.IN)
led=Pin(16,Pin.OUT)
distancia = 0

def sensor_ultra(timer):
    global distancia
    trigger.low()
    utime.sleep_us(2)
    trigger.high()
    utime.sleep_us(5)
    trigger.low()

    while echo.value ==0:
        start =utime.ticks_us()
    while echo.value==1:
        end=utime.ticks_us()

    duracion= end - start
    distancia=(duracion*0.0343)/2
    print("Distancia:",distancia,"cm")

timer.init(freq=1,mode=Timer.PERIODIC,callback=sensor_ultra)

while True:
    if distancia<7:
        led.value(1)
    else:
        led.value(0)