import machine
import time

TRIGGER_PIN = 23
ECHO_PIN = 22
GREEN_LED_PIN = 21
RED_LED_PIN = 19
BUZZER_PIN = 18

trigger = machine.Pin(TRIGGER_PIN, machine.Pin.OUT)
echo = machine.Pin(ECHO_PIN, machine.Pin.IN)
green_led = machine.Pin(GREEN_LED_PIN, machine.Pin.OUT)
red_led = machine.Pin(RED_LED_PIN, machine.Pin.OUT)
buzzer = machine.Pin(BUZZER_PIN, machine.Pin.OUT)

def get_distance():
    try:
        trigger.off()
        time.sleep_us(2)
        trigger.on()   
        time.sleep_us(10)
        trigger.off()  

    
        pulse_time = machine.time_pulse_us(echo, 1)
        if pulse_time < 0:
            raise ValueError("No pulse detected")

        distance = (pulse_time * 0.0343) / 2
        return distance
    except Exception as e:
        print(f"Error in get_distance: {e}")
        return -1 

while True:
    
    distance = get_distance()
    
    if distance > 0 and distance < 20: 
        print("Motion Detected!")  
        green_led.on()  
        buzzer.on()     
        red_led.off()   

        time.sleep(2)   
        
        green_led.off()  
        buzzer.off()     

    else:
        
        green_led.off()
        buzzer.off()
        red_led.on()
        time.sleep(0.5)
        red_led.off()
        time.sleep(0.5)