# MQ4 Gas Leak Detector

Day 8 of the 100 Days 100 IoT Projects collection. Board: ESP32.

An MQ-4 sensor on the ESP32 watches for methane and sounds a buzzer when levels spike. Practical safety project with analog threshold alarms.

## How it works

The MQ-4's sensing element changes resistance in the presence of methane, which the ESP32 reads as a shifting analog voltage. Once that voltage crosses a calibrated danger threshold, the board sounds the buzzer. The sensor needs a warm-up period before its readings stabilize.

## What you'll learn

- Gas sensor warm-up behavior
- Analog alarm thresholds
- Sensor calibration basics
- Safety system design

Full project (code, wiring diagram, Wokwi simulation): https://github.com/kritishmohapatra/100_Days_100_IoT_Projects/tree/main/MQ4_Gas_Leak_Detection_System_using_ESP32_and_MicroPython

Summary by SkillShop. Code and diagrams belong to the original repo.