from machine import *
from time import *

LDR = ADC(Pin(26))
sensor_voltage = 3.3
trig = Pin(9, Pin.OUT)
echo = Pin(10, Pin.IN)
led = Pin(13, Pin.OUT)
buzzer = PWM(Pin(18))
buzzer.freq(1000)

led.value(0)
buzzer.duty_u16(0)

while True:
    light = LDR.read_u16()
    V = (light/65535)*sensor_voltage
    print("Voltage is",V)

if V>=2:
    led.value(0)
    buzzer.duty_u16(0)
    print("DAY MODE_System Idle")
    sleep(0.2)

else:
    led.value(1)
    buzzer.duty_u16(0)
    print("NIGHT MODE_System Idle")

    trig.value(0)
    sleep_us(2)
    trig.value(1)
    sleep_us(10)
    trig.value(0)

    duration = time_pulse_us(echo, 1)
    distance = (duration*0.0343)/2
    print("distance is", distance)

if distance >50:
    led.value(0)
    buzzer.duty_u16(0)
    print("No one near")

elif distance <20 and distance <=50:
    led.value(1)
    buzzer.duty_u16(0)
    print("Welcome light")

elif distance<=20:
    led.value(1)
    buzzer.duty_u16(20000)
    print("Security Alert")

sleep(0.1)