Editing Alcohol Sensor Based on Gas-Sensitive Resistive Materials (section)

==== System Overview ====
The system is designed to detect alcohol concentration in the surrounding air and provide both visual and audible warnings. It consists of several functional modules, each with a specific role.
The MQ-3 alcohol sensor is used as the sensing element. It detects alcohol vapor and outputs an analog voltage that varies depending on the concentration.
The Arduino Uno acts as the central controller. It reads the analog signal from the sensor, processes the data, and makes decisions based on a predefined threshold.
The LCD1602 display with I2C interface is used to present the measured value in real time. Compared to simpler indicators, the LCD provides a more flexible and readable output.
A red LED serves as a visual indicator. It is turned on when the detected alcohol level exceeds the safe limit.
A buzzer is used as an audible alarm. In this design, a transistor is included to drive the buzzer, ensuring that sufficient current can be supplied.
All modules are powered by the Arduino and share a common ground, forming a simple but complete sensing and alarm system.