Gas Leak Alarm Project Kit - ESP32 + MQ-2 Sensor + NE555 + Breadboard
Build a functional gas leak detection system from components you wired yourself. This kit contains everything needed to construct a working alarm: the MQ-2 gas sensor reads combustible gas concentrations, the ESP32 processes the analog signal and compares it to a safety threshold, and the NE555 timer IC drives an alarm output circuit when dangerous levels are detected. Everything wires together on the included MB-102 breadboard using the 3.3V/5V power supply module and 65 jumper wires.
The MQ-2 detects smoke, butane, LPG, propane, methane, and hydrogen across a 300-10,000 ppm range. For the audible alarm, the NE555 runs in astable mode to produce an oscillating signal that drives a passive piezo buzzer (not included - any standard 5V passive buzzer works and costs under $2). The ESP32's WiFi capability means you can extend the project to send a notification to your phone via IFTTT, Home Assistant, or a simple HTTP webhook whenever the alarm triggers.
What is not included: A passive piezo buzzer for audio output and a USB-C cable for programming the ESP32. The complete step-by-step project guide is in our Projects section and walks through every wiring connection, calibration step, and code upload from scratch. Expected build time is 1.5-2 hours for someone with basic electronics and Arduino experience.
Specifications
| Includes | ESP32 DevKit + MQ-2 Sensor + NE555 IC + Breadboard + Power Module + 65 Jumper Wires |
|---|---|
| Detection | Smoke, H2, CH4, Butane, LPG (300-10,000 ppm) |
| Alarm | NE555-driven piezo circuit (buzzer not included) |
| Connectivity | WiFi + Bluetooth for remote alerts |
| Difficulty | Intermediate |
| Build Time | 1.5 hours |
Frequently Asked Questions
Does this kit include a buzzer for the alarm sound?
No. A passive piezo buzzer is not included but is inexpensive and widely available - under $2 at any electronics retailer or online. The NE555 timer in the kit generates the oscillating signal; the buzzer simply connects to the output. The project guide specifies exactly which type to use and how to wire it.
Can this alarm send a notification to my phone?
Yes - this is one of the project extensions covered in the guide. The ESP32 connects to your WiFi and sends an HTTP request to services like IFTTT (free), Pushover, or Home Assistant when the MQ-2 detects gas above the threshold. You can also run a web server on the ESP32 itself and view live gas concentration from any browser on your network.
What gases does the MQ-2 sensor detect?
The MQ-2 detects smoke, LPG, butane, propane, methane, hydrogen, and alcohol vapors. It is a broad-spectrum combustible gas sensor useful for general home safety monitoring and leak detection, but not precise enough to identify a single gas type or provide certified safety measurement. It functions as a practical alarm trigger for educational and DIY applications.
How difficult is this project for a beginner?
This kit is rated Intermediate. You should be comfortable with basic breadboard wiring, installing Arduino IDE, and uploading code to an ESP32. If this is your first project, start with the Complete Prototyping Starter Kit and the Temperature Monitor build (rated Beginner) to get familiar with the workflow before tackling this one. The project guide provides all code and wiring diagrams.
Is the MQ-2 accurate enough for real home safety use?
The MQ-2 is a reliable educational and DIY gas sensor but is not a certified safety device. For life-safety applications in residential or commercial buildings, use a UL-listed gas or smoke detector. This kit is designed for learning electronics concepts, understanding sensor integration, and exploring IoT alerting - not as a replacement for certified safety equipment.