Ethanol is a chemical compound commonly encountered in everyday life and is
present in food, beverages, cosmetics, and other daily necessities. It is produced
through the fermentation of plants and fruits containing carbohydrate sugars.
Permissible ethanol is categorized into three groups: Group A (less than 5%),
Group B (between 5-20%), and Group C (between 20-55%). However, many
alcoholic beverages do not specify the group and concentration of ethanol, making
it difficult for consumers and laboratories to determine the ethanol content. This
study aims to design an ethanol detection device using an ATmega328P
microcontroller and an MQ-3 gas sensor, displaying outputs via an LED, buzzer,
and 16 x 2 LCD. The MQ-3 sensor can detect changes in ethanol concentration in
liquids. The sensor's transfer function is y = 3.95x + 514, where y represents the
ethanol concentration (%) and x is the decimal bit value obtained from converting
the analog voltage output to digital by the ATmega328P. The measurement results
are still digital data output from the ATmega328P and have not yet been displayed
on the LCD. The average relative error (deviation) of the device is 3.8%.