There are many MQ-X sensors available on the market for different uses but we are here to use MQ-3.
The resistance of these sensors changes when fumes from alcohol come into contact with the MQ-3 sensor.
The LM393 IC is an inbuilt module in the MQ-3 sensor to convert voltage signals to a detectable range.
Here we used the LM358 IC for converting analog output to digital output.
A buzzer is placed to indicate high alcohol levels.