MQ-4 Methane Gas Sensor (CNG) 🔍

The MQ-4 Methane Gas Sensor is a proven sensing element engineered to detect methane (CH4), the primary component of natural gas and CNG. Ideal for building custom gas detection modules and instruments, it suits both electronics hobbyists and engineers integrating sensors into Arduino, Raspberry Pi, and other microcontroller-based systems.

Key Features ⚡

• High sensitivity to methane for reliable detection at low concentrations.
• Wide detection range: 200–10,000 ppm (parts per million).
• Durable construction for long service life in continuous monitoring applications.
• Efficient operation suited to embedded and battery-backed systems when properly power-managed.
• Fast response: quickly tracks changes in methane concentration for near real-time monitoring.

Technical Specifications ⚙️

The following specifications are provided for the MQ-4 sensing element:

• Sensing material: SnO2 (Tin Dioxide)
• Concentration range: 200–10,000 ppm CH4
• Load resistance: Adjustable (external resistor required in the measurement circuit)
• Heating resistance (RH): 31 Ω ± 3 Ω
• Heating current: ≤ 180 mA (depends on heater drive voltage)
• Response time: ≤ 10 s (70% response)
• Operating temperature: −20°C to +50°C

Integration with Arduino, Raspberry Pi, and Microcontrollers 🤖

For practical use, the MQ-4 sensing element is typically mounted on a breakout module that includes a load resistor and forms a voltage divider. The resulting analog signal can be read by:

• Arduino or similar boards via an analog input.
• Raspberry Pi through an external ADC module (e.g., MCP3008) since Pi boards lack native analog inputs.

Best practices:

• Allow warm-up/burn-in per the datasheet before calibration and use.
• Perform calibration in clean air and (if available) in a known methane concentration to establish R0 and compute Rs/R0.
• Provide a stable power supply capable of the heater’s current demand (up to 180 mA).
• Consider environmental factors (temperature, humidity, airflow) in enclosure and placement.

Applications 🚨

• Residential and industrial gas leak detection systems
• Gas safety devices for homes, workshops, and facilities
• Environmental monitoring and data-logging projects
• Portable gas detectors and handheld testers

Engineering Notes 🛠️

• This device is a sensor component; it is not a certified safety detector. For life-safety applications, use certified detection systems.
• Combine with appropriate electronics components (load resistor, ADC, signal conditioning) when designing sensor modules.
• Heater power dominates consumption; use duty-cycling or power management if operating from batteries.

Datasheet 📄