from machine import Pin
import utime

trigger = Pin(14, Pin.OUT)
echo = Pin(15, Pin.IN)
led = Pin('LED', Pin.OUT)

def ultra():
    trigger.low()
    utime.sleep_us(2)
    trigger.high()
    utime.sleep_us(5)
    trigger.low()
    while echo.value() == 0:
        signaloff = utime.ticks_us()
    while echo.value() == 1:
        signalon = utime.ticks_us()
    timepassed = signalon - signaloff
    distance = (timepassed * 0.0343) / 2
    print("Object at",distance,"cm")

    if distance < 15:
        led.high()
    else:
        led.low()

while True:
    ultra()
    utime.sleep(1)