from machine import Pin, time_pulse_us
import time

# Define pins
TRIG_PIN = Pin(5, Pin.OUT)
ECHO_PIN = Pin(18, Pin.IN)
BUZZER_PIN = Pin(19, Pin.OUT)
LED_GREEN = Pin(13, Pin.OUT)
LED_YELLOW = Pin(12, Pin.OUT)
LED_RED = Pin(14, Pin.OUT)

def get_distance():
    # Send a pulse to trigger the ultrasonic sensor
    TRIG_PIN.value(0)
    time.sleep_us(2)
    TRIG_PIN.value(1)
    time.sleep_us(10)
    TRIG_PIN.value(0)
    
    # Measure the duration of the echo pulse
    duration = time_pulse_us(ECHO_PIN, 1, 1000000)
    # Calculate distance (duration in microseconds * speed of sound / 2)
    distance = (duration / 2) / 29.1  # cm
    
    return distance

def update_leds(distance):
    # Set LED states based on distance
    if distance > 100:
        LED_GREEN.value(1)
        LED_YELLOW.value(0)
        LED_RED.value(0)
    elif distance <= 100 and distance > 10:
        LED_GREEN.value(0)
        LED_YELLOW.value(1)
        LED_RED.value(0)
    else:
        LED_GREEN.value(0)
        LED_YELLOW.value(0)
        LED_RED.value(1)

def main():
    while True:
        distance = get_distance()
        print("Distance:", distance, "cm")
        
        # Update LEDs based on distance
        update_leds(distance)
        
        # Activate buzzer if distance is less than 10 cm
        if distance <= 10:
            BUZZER_PIN.value(1)
        else:
            BUZZER_PIN.value(0)
        
        time.sleep(0.2)

# Run the main loop
main()