1. This document describes a microcontroller-based LPG gas detector that uses an MQ-5 gas sensor to detect LPG leaks and sends SMS alerts via a GSM module. 2. When the sensor detects LPG above a threshold, the microcontroller turns on an LED, buzzer, and exhaust fan to remove the gas. It also sends an "LPG LEAKAGE" message to a stored mobile number. 3. The system uses an ATmega16 microcontroller, SIM300 GSM module, MQ-5 gas sensor, LED, buzzer, and exhaust fan. It operates on a 5V power supply derived from a 230V AC transformer.