MQ-2 Smoke / Hydrogen / Butane / LPG / Methane Gas Sensor Detector Module -- Versatile Multi-Gas Detection

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. Its broad detection range of 300–10,000 ppm makes it one of the most versatile sensors in the MQ family. The module features dual signal outputs with an analog output (0–5V) proportional to gas or smoke concentration and a digital TTL output with an adjustable threshold via the onboard potentiometer. With fast response, long service life, and a simple 4-pin interface, it's ideal for Arduino-based smoke alarms, gas leak detection, and safety projects.

🔧 How It Works

1. The sensor's internal heater raises the tin dioxide (SnO₂) element to its operating temperature
2. When combustible gas molecules or smoke particles contact the heated surface, the sensor's electrical resistance decreases proportionally to concentration
3. The onboard voltage divider converts the resistance change into an analog voltage (0–5V) on the AO pin -- higher concentration produces higher voltage
4. The LM393 comparator checks the signal against the potentiometer threshold and drives the DO pin HIGH when exceeded

⚡ 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 DO status LED for visual feedback
• Fast Response & Recovery -- Quick detection and return to baseline
• 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

Arduino, jumper wires, and USB cable are not included.

🔌 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

🎯 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
• 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 -- not a certified safety device
• Allow a 24–48 hour initial burn-in for best accuracy on first use
• The MQ-2 is a broad-spectrum sensor -- it responds to multiple gases and smoke simultaneously and cannot differentiate between them
• Raw analog readings are not direct PPM values -- calibration against known concentrations is required
• The sensor draws up to 160 mA -- use an external 5V supply if experiencing unstable readings
• Keep the sensor away from direct airflow (fans, HVAC vents) that could dilute gas or smoke concentrations

🏪 About Envistia Mall

Envistia Mall is a US-based electronics retailer specializing in development boards, sensors, modules, and components for makers, engineers, and educators. We are committed to providing quality products with excellent customer service.

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Visit our eBay Store for more gas sensor modules including the MQ-5, MQ-7, MQ-9, and MQ-135, plus Arduino-compatible development boards, jumper wires, and electronic components for your next project.