from machine import Pin, PWM, time_pulse_us
import time

trigger = Pin(3, Pin.OUT)
echo = Pin(2, Pin.IN)

buzzer = PWM(Pin(14))
buzzer.duty_u16(0)

led = Pin(16, Pin.OUT)

def get_distance():
    trigger.low()
    time.sleep_us(2)
    trigger.high()
    time.sleep_us(10)
    trigger.low()

    duration = time_pulse_us(echo, 1)
    distance = (duration * 0.0343) / 2
    return distance

while True:
    try:
        dist = get_distance()

        print("Distance: {:.2f} cm".format(dist))

        if dist < 20:
            buzzer.freq(1000)
            buzzer.duty_u16(30000)
            time.sleep(0.3)
            buzzer.deinit()
            buzzer = PWM(Pin(14))
        if (dist>300):
            led.on()

        else:
            led.off()
            buzzer.deinit()

        time.sleep(2)

    except:
        print("Error reading sensor")