from machine import Pin, ADC, PWM
from time import sleep

# MQ2 Gas Sensor
mq2 = ADC(26)  # MQ2 Analog Output connected to GP26 (ADC0)
threshold = 25000  # Adjust based on testing

# Stepper Motor Control Pins
step_pin = Pin(16, Pin.OUT)  # STEP pin to GP16
dir_pin = Pin(17, Pin.OUT)   # DIR pin to GP17

# Buzzer (PWM for sound)
buzzer = PWM(Pin(15))  # Buzzer on GP15
buzzer.freq(1000)  # Set frequency to 1kHz

# Function to turn buzzer on/off
def alarm_on():
    buzzer.duty_u16(30000)  # Set duty cycle (volume)
    
def alarm_off():
    buzzer.duty_u16(0)  # Turn off buzzer

# Function to rotate stepper motor
def rotate_motor(steps, direction):
    dir_pin.value(direction)  # 1 = Clockwise, 0 = Counterclockwise
    for _ in range(steps):
        step_pin.value(1)
        sleep(0.001)
        step_pin.value(0)
        sleep(0.001)

# Main loop
while True:
    gas_level = mq2.read_u16()  # Read gas sensor value
    print("Gas Level:", gas_level)

    if gas_level > threshold:
        print("Gas detected! Turning on fan and alarm.")
        alarm_on()  # Turn on buzzer
        rotate_motor(200, 1)  # Rotate stepper motor
    else:
        print("Gas level normal.")
        alarm_off()  # Turn off buzzer

    sleep(1)  # Wait before next reading