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

led1 = Pin(15, Pin.OUT)
led2 = Pin(2, Pin.OUT)
led3 = Pin(4, Pin.OUT)
sensor = HCSR04(trigger_pin = 18, echo_pin = 5)

while True:
    distance = sensor.distance_cm()
    if distance < 20:
        led1.value(1)
        led2.value(0)
        led3.value(0)
    elif distance < 30:
        led1.value(1)
        led2.value(1)
        led3.value(0)
    elif distance < 40:
        led1.value(1)
        led2.value(1)
        led3.value(1)
    else:
        led1.value(0)
        led2.value(0)
        led3.value(0)