from machine import ADC,Pin
from time import sleep

LED_green = Pin(16, Pin.OUT)
LED_red = Pin(17, Pin.OUT)
buzzer = Pin(18, Pin.OUT)

AnalogIn = ADC(0)                     # ADC channel 0
Conv = 3.3 / 65535                   # Conversion factor

while True:                           # Do forever
    sensor_value= AnalogIn.read_u16()     # Read temp
    gas_value = sensor_value * Conv       # Convert to Volts
    #Temp = (mV - 500.0) / 10.0           # Convert to temp
    gas_str = str(gas_value)[:5]          # Convert to string
    sleep(0.5)                            # Wait 1 second
    print(gas_value)
    if gas_value < 1:
       buzzer.off()
       LED_green.on()
       LED_red.off()
       sleep(0.1)
       LED_green.off()
       LED_red.off()
    elif gas_value >1 and gas_value < 3:
       buzzer.off()
       LED_green.off()
       LED_red.on()
       sleep(0.1)
       LED_green.off()
       LED_red.off()
    elif gas_value > 3:
        buzzer.on()
        LED_red.on()