from machine import Pin,ADC,PWM
import time
#ultrasonic sensor (HC-SR04)
trigger = Pin(16,Pin.OUT)
echo = Pin(17,Pin.IN)
ldr = ADC(26)
red_led = Pin(14,Pin.OUT)
green_led = Pin(15,Pin.OUT)
buzzer = PWM(Pin(13))
buzzer.freq(1000)
INTRUDER_DISTANCE = 50
DDARK_THRESHOLD = 30000
def measure_distance():
    trigger.low()
    time.sleep_us(2)
    trigger.high()
    time.sleep_us(10)
    trigger.low()
    while echo.value()==0:
        start=time.tick_us()
    while echo.value()==1:
        end =time.tick_us() 
        duration = time.ticks_diff(end, start)
        distance = (duration * 0.0343) / 2
    return distance
print("Security System Initialized")
print("----------------------------------")

# ---------------- MAIN LOOP ----------------
while True:
        distance = measure_distance()
        light_value = ldr.read_u16()

    print(f"Distance: {distance:.1f} cm | LDR: {light_value}")

    # 🔴 PRIORITY 1: INTRUDER ALERT
    if distance < INTRUDER_DISTANCE:
        print("🚨 INTRUDER DETECTED!")
        red_led.value(1)
        green_led.value(0)
        buzzer.duty_u16(30000)   # Buzzer ON

    # 🟢 PRIORITY 2: ENVIRONMENT STATUS
    else:
        red_led.value(0)
        buzzer.duty_u16(0)       # Buzzer OFF

        if light_value > DARK_THRESHOLD:
            print("🌙 Night Watch Mode")
            green_led.toggle()
            time.sleep(0.5)
        else:
            print("☀ Day Safe Mode")
            green_led.value(1)
            time.sleep(0.5)