import machine
import time

a = 1

# Define GPIO pins
trig = machine.Pin(1, machine.Pin.OUT)
echo = machine.Pin(0, machine.Pin.IN)
red_led = machine.Pin(28, machine.Pin.OUT)
yellow_led = machine.Pin(26, machine.Pin.OUT)
green_led = machine.Pin(21, machine.Pin.OUT)

def get_distance():
  # Send ultrasonic pulse
  trig.low()
  time.sleep_us(2)
  trig.high()
  time.sleep_us(10)
  trig.low()

  # Measure pulse duration
  pulse_start = time.ticks_us()
  while echo.value() == 0:
    pass
  pulse_start = time.ticks_us()

  while echo.value() == 1:
    pass
  pulse_end = time.ticks_us()

  pulse_duration = pulse_end - pulse_start
  distance = pulse_duration * 0.034 / 2

  return distance

def light_leds(distance):
  if 2 < distance < 15:  # Adjust based on sensor's minimum distance
    red_led.value(1)
    print("Very close obstacle!")
  elif 10 < distance < 30:
    red_led.value(1)  # Red for close proximity
  elif distance < 50:
    yellow_led.value(1)  # Yellow for caution
  else:
    green_led.value(1)  # Green for safe distance

  # Turn off unused LEDs
  red_led.value(0) if distance >= 30 else red_led.value(1)
  yellow_led.value(0) if distance < 10 or distance >= 50 else yellow_led.value(1)
  green_led.value(0) if distance < 50 else green_led.value(1)

while (a == 1):
  distance = get_distance()
  # Print calculated distance for debugging (optional)
  print("Distance:", distance, "cm")
  light_leds(distance)
  time.sleep(5)
  if 2 < distance < 3:
    print("The car had hit the obstacle!!\n")
    break