MQ-2 Gas Sensor Module For H2, LPG, CH4, CO, Smoke or Propane Detector Module
🔥 MQ-2 Gas Sensor Module
Flammable Gas Detection • Smoke Monitoring • Safety Applications
The MQ-2 Gas Sensor Module is a widely used gas detection sensor designed to detect flammable and combustible gases such as Hydrogen (H₂), LPG, Methane (CH₄), Carbon Monoxide (CO), Propane, and Smoke. It is commonly used in gas leakage detection systems, fire safety systems, and air quality monitoring projects.
📊 Infographic Overview
🔹 Basic Specifications
| Feature | Details |
|---|---|
| 🔌 Operating Voltage | 5V DC |
| ⚡ Current Consumption | ~150 mA |
| 🌡 Heating Consumption | < 900 mW |
| 📏 Detection Range | 200 – 10,000 ppm |
| ⏱ Response Time | < 10 seconds |
| 📡 Output Types | Analog (A0) & Digital (D0) |
| 🔧 Sensitivity Adjustment | Yes (Potentiometer) |
🧪 Detectable Gases
The MQ-2 sensor is highly sensitive to several combustible gases.
| Gas | Description |
|---|---|
| 🔬 Hydrogen (H₂) | Highly flammable gas |
| 🔥 LPG | Liquefied petroleum gas used in cooking |
| ⛽ Methane (CH₄) | Natural gas |
| ☠ Carbon Monoxide (CO) | Toxic combustion gas |
| 🚬 Smoke | Fire and burning detection |
| 🔥 Propane | Fuel gas used in heaters and grills |
🔌 Pin Configuration
| Pin | Function |
|---|---|
| VCC | 5V Power Supply |
| GND | Ground |
| A0 | Analog output (gas concentration level) |
| D0 | Digital output (threshold detection) |
⚙️ Working Principle
The MQ-2 sensor operates using the metal oxide semiconductor (MOS) gas sensing principle.
Step-by-Step Operation
1️⃣ A heating coil warms the internal sensing material.
2️⃣ The sensing material (usually Tin Dioxide – SnO₂) reacts with gas molecules.
3️⃣ When combustible gases are present, the sensor resistance changes.
4️⃣ This change is converted into analog voltage output.
5️⃣ The module’s comparator circuit can trigger a digital signal when gas concentration exceeds a preset threshold.
🧩 Main Components
🔹 MQ-2 Gas sensing element
🔹 Heating coil
🔹 LM393 comparator chip
🔹 Adjustable potentiometer (sensitivity control)
🔹 Power and output pins
📐 Sensor Module Layout
MQ-2 Gas Sensor Module
┌───────────────┐
│ MQ-2 Sensor │
│ Gas Probe │
└───────────────┘
🔧 Sensitivity Adjuster
(Potentiometer)
┌─────┬─────┬─────┬─────┐
│ VCC │ GND │ A0 │ D0 │
└─────┴─────┴─────┴─────┘
🤖 Common Applications
🔹 Gas leakage detection systems
🔹 Fire and smoke detection systems
🔹 Smart kitchen safety systems
🔹 Industrial safety monitoring
🔹 Smart home gas alarm systems
🔹 Environmental monitoring projects
🔌 Compatible Microcontrollers
The MQ-2 module easily interfaces with popular development boards such as:
Arduino Uno
ESP32
Arduino Nano
Raspberry Pi
💡 Advantages
✅ Detects multiple flammable gases
✅ Low cost and easy to integrate
✅ Analog and digital outputs available
✅ Adjustable sensitivity
✅ Ideal for DIY electronics and robotics projects
⚠️ Limitations
❌ Requires preheating time (24 hours recommended for calibration)
❌ Cannot identify specific gas type precisely
❌ Sensitive to humidity and temperature changes
❌ Consumes relatively high current due to heating element
🔧 Example Project Idea
🏠 Smart Gas Leakage Alarm System
Components
MQ-2 Gas Sensor Module
ESP32 or Arduino Uno
Buzzer
LED Indicator
LCD/OLED Display
Features
✔ Detect gas leakage in kitchens
✔ Trigger buzzer alarm
✔ Display gas level
✔ Send IoT alert to smartphone
