This document describes a microcontroller-based automatic engine locking system for drunken drivers. The system uses an AT89S52 microcontroller and various hardware components like an alcohol detection sensor, buzzer, LCD display, motors and more. It detects alcohol levels using a sensor and locks the engine by activating a relay if alcohol is detected above the set limit, simulating the locking process. The system is programmed using Keil software and aims to prevent accidents caused by drunk driving.