import machine
import dht
import time

from machine import Pin, ADC

# Define pin and variables for DHT22
DHTPIN = 4
dht_sensor = dht.DHT22(Pin(DHTPIN))

# Define pins for HC-SR04 ultrasonic sensor
TRIG_PIN = 18
ECHO_PIN = 19

# Define pin for photoresistor module
PHOTO_PIN = 34

# Define pins for LED and Buzzer
LED_PIN = 2
BUZZER_PIN = 13

# Fixed resistance value in voltage divider circuit (ohms)
R_fixed = 10000.0  # 10k ohms

# Initial light value (lux) from photoresistor datasheet
initialLux = 500.0

# Initialize ADC for photoresistor
photoresistor = ADC(Pin(PHOTO_PIN))
photoresistor.atten(ADC.ATTN_11DB)  # Set ADC sensitivity

# Initialize pins
led = Pin(LED_PIN, Pin.OUT)
buzzer = Pin(BUZZER_PIN, Pin.OUT)
trigger = Pin(TRIG_PIN, Pin.OUT)
echo = Pin(ECHO_PIN, Pin.IN)

# Function to read DHT22 sensor
def read_dht22():
    dht_sensor.measure()
    humidity = dht_sensor.humidity()
    temperature = dht_sensor.temperature()
    return humidity, temperature

# Function to read photoresistor value
def read_photoresistor():
    light_level = photoresistor.read()
    return light_level

# Function to calculate lux from photoresistor value
def calculate_lux(light_level):
    V_in = light_level * (3.3 / 4095.0)  # ESP32 uses 3.3V reference voltage
    R_photo = (3.3 * R_fixed / V_in) - R_fixed
    lux = initialLux * (R_photo / R_fixed)
    return lux

# Function to control LED based on lux value
def control_led(lux_value):
    ILLUMINATION = 500  
    if lux_value <= ILLUMINATION:  
        print("Turning LED ON")
        led.value(1)
    else:
        print("Turning LED OFF")
        led.value(0)


# Function to measure distance using HC-SR04 sensor
def measure_distance():
    trigger.value(0)
    time.sleep_us(2)
    trigger.value(1)
    time.sleep_us(10)
    trigger.value(0)
    duration = machine.time_pulse_us(echo, 1)  # Measure high pulse duration
    if duration > 0:
        distance = (duration * 0.034) / 2  # Convert to cm
    else:
        distance = 0
    return distance

# Function to control buzzer based on distance and humidity
def control_buzzer(distance, humidity):
    if distance < 20:  # Activate buzzer if object detected within threshold
        led.value(1)
        pwm = machine.PWM(buzzer, freq=1000, duty=512)  # PWM buzzer at 1000Hz
        time.sleep_ms(300)
        pwm.deinit()  # Turn off PWM
        led.value(0)
        time.sleep_ms(300)
    elif humidity > 50:  # Activate buzzer if humidity exceeds 50%
        led.value(1)
        pwm = machine.PWM(buzzer, freq=1000, duty=512)  # PWM buzzer at 1000Hz
        time.sleep_ms(300)
        pwm.deinit()  # Turn off PWM
        led.value(0)
        time.sleep_ms(300)
    else:
        led.value(0)  # Turn off LED if no object detected

# Main loop in Micropython
while True:
    humidity, temperature = read_dht22()
    print("Humidity:", humidity, "%\tTemperature:", temperature, "°C")

    light_level = read_photoresistor()
    lux = calculate_lux(light_level)
    print("Raw Light level:", light_level)
    print("Lux level:", lux)

    control_led(lux)

    distance = measure_distance()
    print("Distance:", distance, "cm")

    print("Current time:", time.time())
    time.sleep(1)

    control_buzzer(distance, humidity)

    time.sleep_ms(100)