Smart GSM Based Anti Drunk Car Alert System

The Smart GSM Based Anti Drunk Car Alert System is designed to actively prevent individuals from driving under the influence of alcohol. At the heart of the system is an Arduino Uno microcontroller, which continuously monitors the environment using an MQ-3 alcohol sensor module placed near the driver. When the sensor detects ethanol vapor in the breath, it outputs an analog voltage proportional to the alcohol concentration, which the Arduino reads and processes using the MQunifiedsensor library. If the measured alcohol level exceeds a predefined safety threshold, the system triggers two immediate actions. First, it activates a relay module that interrupts the vehicle's ignition or power circuit, effectively preventing the car from starting or moving. Second, it utilizes a SIM800L GSM module equipped with a 2G capable SIM card to transmit an emergency warning SMS to a pre-programmed recipient, such as a family member or fleet manager. The software relies on the SoftwareSerial and Fona libraries to facilitate reliable serial communication between the Arduino and the GSM module. Power is managed via a dedicated power supply ensuring stable operation for both the microcontroller and the cellular module. Through this integrated loop of sensing, processing, and acting, the system provides an automated layer of road safety.