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

# Gas sensor on GPIO34 (ADC)
gas_sensor = ADC(Pin(34))
gas_sensor.atten(ADC.ATTN_11DB)   # 0–3.3V range
gas_sensor.width(ADC.WIDTH_12BIT) # 12-bit resolution (0–4095)

# Buzzer on GPIO15 with PWM
buzzer = PWM(Pin(15))
buzzer.deinit()  # make sure it's OFF initially

THRESHOLD = 2000
FREQ = 1000  # buzzer frequency (Hz)

while True:
    gas_value = gas_sensor.read()
    print("Gas Value:", gas_value)

    if gas_value > THRESHOLD:
        buzzer.init(freq=FREQ, duty=512)  # 50% duty cycle sound ON
    else:
        buzzer.deinit()  # turn OFF buzzer

    sleep(0.5)