from machine import *
from time import *

led = Pin(21, Pin.OUT)
ldr = ADC(Pin(28))
sensor_voltage = 3.3


trig = Pin(18, Pin.OUT)
echo = Pin(20, Pin.IN)
led = Pin(21, Pin.OUT)
buzzer = PWM(Pin(15))
buzzer.freq(1000)

while True:

    light = ldr.read_u16()
    V = (light / 65535) * sensor_voltage

    if ldr>1.5  :        
        ldr.value(1)
        ldr.value(0)
        buzzer.duty_u16(0)
        sleep(0.5)
        
    else:              
        rled.value(0)
        gled.value(1)

    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

    if distance>100 :
        led.value(0)
        buzzer.duty_u16(0)
    

    elif distance >50 and distance <= 100:
        led.value(1)
        buzzer.duty_u16(0)

    elif distance<= 50:
        led.valu(1)
        buzzer.duty_u16(1)
        
    else:
        led.value(1)
        buzzer.duty_u16(20000)

    sleep(0.5)