Alcohol sensor using comparator IC LM358

Circuit Description:

1. LM358 Comparator:
   • The LM358 operational amplifier is configured as a comparator. It compares the voltage from the gas sensor module with a reference voltage.
2. Gas Sensor Module:
   • The gas sensor module, specifically designed for alcohol detection (MQ series or similar), produces a variable voltage output based on the concentration of alcohol vapor.
3. Potentiometer:
   • The potentiometer is used to set the reference voltage for the LM358 comparator. It determines the threshold level for detecting the presence of alcohol.
4. Resistor (R1):
   • R1 is connected between the positive voltage rail and the output of the gas sensor module. It is used for biasing and limiting current.
5. LED and Buzzer (Optional):
   • An LED and/or a buzzer can be connected to the output of the LM358 comparator for visual and audible indications when alcohol vapor is detected.