from machine import Pin, ADC, PWM
import time

# MQ2 Gas Sensor
gas_sensor = ADC(26)  # MQ2 sensor connected to GP26 (ADC0)
ppm_threshold = 80  # Gas detection threshold in PPM

# Buzzer (Using PWM for continuous beep)
buzzer = PWM(Pin(15))
buzzer.freq(1000)  # Set frequency to 1kHz (adjustable)

# Servo Motor (Fan)
servo = PWM(Pin(14))  # Servo on GP14
servo.freq(50)  # 50Hz PWM frequency

def set_servo_angle(angle):
    duty = int((angle / 180) * 6000 + 2000)  
    print(f"Setting servo to {angle}° (Duty: {duty})")
    servo.duty_u16(duty)
    time.sleep(0.5)

def convert_gas_value_to_ppm(analog_value):
    return (analog_value / 65535) * 100  # Adjust scaling if needed

while True:
    analog_value = gas_sensor.read_u16()
    ppm_value = convert_gas_value_to_ppm(analog_value)
    
    print(f"Raw ADC Value: {analog_value}, Gas Level: {ppm_value:.2f} PPM")

    if ppm_value > ppm_threshold:
        print("Gas detected! Turning ON fan and buzzer.")
        buzzer.duty_u16(30000)  # 50% duty cycle (ON)
        set_servo_angle(90)  # Move fan to 90 degrees
    else:
        print("Gas level normal. Turning OFF fan and buzzer.")
        buzzer.duty_u16(0)  # Stop buzzer (OFF)
        set_servo_angle(0)  # Reset fan position

    time.sleep(1)