MQ-2 Smoke Hydrogen Butane LPG Methane Gas Sensor Detector Module

📋 Overview

The MQ-2 smoke and gas sensor detector module detects smoke and a wide range of combustible gases including hydrogen (H₂), methane (CH₄), butane, alcohol, and LPG (Liquified Petroleum Gas). Its broad detection range makes it one of the most versatile gas sensors in the MQ family, suitable for both home and industrial use.

The module features dual signal outputs: an analog output (0V to ~5V) that increases with gas or smoke concentration, and a digital TTL output that signals when concentration exceeds an adjustable threshold. The threshold is easily set using the onboard potentiometer. With fast response and recovery characteristics, long service life, and reliable stability, the MQ-2 is a popular choice for smoke alarms, gas leak detection, and Arduino-based safety projects.

⭐ Key Features

• Smoke & Multi-Gas Detection — Detects smoke, hydrogen, methane, butane, alcohol, and LPG
• Wide Detection Range — 300–10,000 ppm for flammable gases
• Dual Signal Output — Analog (AO) and digital TTL (DO) outputs for flexible integration
• Adjustable Threshold — Onboard potentiometer to set the digital output trigger level
• Indicator LEDs — Power LED and digital output (DO) status LED for visual feedback
• Fast Response & Recovery — Quick detection and return to baseline for reliable monitoring
• Simple 4-Pin Interface — VCC, GND, AO, DO — no library required
• 5V Compatible — Works directly with Arduino, ESP8266, and other 5V development boards

📊 Specifications

📦 What's in the Box

• 1x MQ-2 Smoke & Gas Sensor Detector Module

🔌 Compatible With

• Arduino (Uno, Mega, Nano, Pro Mini, and compatibles)
• ESP8266 and ESP32 development boards
• Raspberry Pi (with ADC module for analog reading)
• STM32, Teensy, and other 5V-compatible microcontrollers
• Any microcontroller with analog input and 5V power supply

🚀 Getting Started

1. Connect VCC to 5V, GND to GND, AO to an analog input pin (e.g., A0), and DO to a digital input pin (e.g., D2)
2. Upload a basic analogRead() sketch to your Arduino — no special library is required
3. Open the Serial Monitor at 9600 baud and allow the sensor 2–5 minutes to warm up
4. Observe the baseline reading in clean air, then introduce smoke or gas near the sensor to see the value increase
5. Adjust the onboard potentiometer to set the digital output threshold for your application

💡 Tip: A safe way to test smoke detection is to light a match, blow it out, and hold the smoldering match near the sensor. See our complete User Guide linked below for detailed wiring diagrams, sample Arduino code, and troubleshooting tips.

📌 Pinout

🎯 Typical Applications

• Smoke detection and fire alarm systems
• Home gas leak detection (kitchen, furnace room, garage)
• Industrial gas monitoring systems
• Arduino and microcontroller safety projects
• Portable gas and smoke sniffers
• Smart home automation — trigger ventilation fans, alarms, or shut-off valves when gas or smoke is detected
• Air quality monitoring stations
• Educational and STEM projects

⚠️ Important Notes

• The sensor element gets hot during operation — do not touch the metal mesh cylinder while powered
• This module is for gas and smoke detection and indication only — it is not a certified safety device and should not be used as the sole protection against gas leaks or fire
• Allow a 24–48 hour initial burn-in for best accuracy on first use; subsequent warm-ups take only 2–5 minutes
• The MQ-2 is a broad-spectrum sensor — it responds to multiple gases and smoke simultaneously and cannot differentiate between gas types on its own
• Raw analog readings are not direct PPM values — calibration against known concentrations is required for PPM conversion
• The sensor draws up to 160 mA — use an external 5V supply if powering multiple sensors or experiencing unstable readings
• Keep the sensor away from direct airflow (fans, HVAC vents) that could dilute gas or smoke concentrations

📄 Documentation & Resources

• User Guide — Wiring, Arduino Code, Calibration & Troubleshooting
• All Sensor, Detector & Input Module Guides