from machine import Pin, Timer
import time

class UltrasonicLED:
    def __init__(self, trig_pin, echo_pin, led_pin):
        self.trig = Pin(trig_pin, Pin.OUT)
        self.echo = Pin(echo_pin, Pin.IN)
        self.led = Pin(led_pin, Pin.OUT)
        self.led_state = False
        self.blink_timer = Timer(-1)
        
        self.trig.value(0)
        
        time.sleep(2)  
    def _blink(self, timer):
        self.led.value(self.led_state)
        self.led_state = not self.led_state

    def measure_distance(self):
        self.trig.value(1)
        time.sleep_us(10)
        self.trig.value(0)

        timeout = time.ticks_add(time.ticks_us(), 30000)
        start = time.ticks_us()
        while self.echo.value() == 0 and time.ticks_diff(time.ticks_us(), timeout) < 0:
            pass

        while self.echo.value() == 1:
            end = time.ticks_us()

        pulse_duration = time.ticks_diff(end, start)
        distance = (pulse_duration * 0.0343) / 2
        return distance

    def run(self):
        while True:
            distance = self.measure_distance()
            if 0 < distance <= 200:
                period = int(distance * 9.5)
                self.blink_timer.init(period=period, mode=Timer.PERIODIC, callback=self._blink)
            else:
                self.blink_timer.deinit()
                self.led.value(0)
            time.sleep(2)

sensor = UltrasonicLED(18, 19, 0)
sensor.run()