Methane Natural Gas Sensor MQ-4

MQ-4 Methane & Natural Gas Sensor
The sensor uses a Tin Dioxide (SnO_2) layer that reacts to methane molecules. When methane is present in the air, the sensor's conductivity increases. This change is converted into a voltage signal that your microcontroller can interpret to determine the gas concentration in parts per million (ppm).

Why it’s the Standard for Natural Gas Safety:
• Methane Specificity: The MQ-4 is "tuned" for Methane. This reduces false alarms in environments where other vapours (like cooking smells or cleaning alcohol) might be present, making it much more reliable for home gas-leak detectors.
• Wide Detection Range: It can detect concentrations from 200 ppm to 10,000 ppm. This allows it to identify a small leak long before it reaches the Lower Explosive Limit (LEL), providing a critical window for safety alerts.
• Dual Output Utility:
* Analog (A0): Provides a variable voltage (0V to 5V) that correlates to the concentration of gas. This is essential for monitoring if a leak is getting worse over time.
* Digital (D0): Can be used as a simple "on/off" switch to trigger an emergency exhaust fan or a siren if a pre-set safety limit is breached.
• Adjustable Sensitivity: The onboard potentiometer lets you calibrate the digital "trigger" point. You can set it to be highly sensitive for industrial pipelines or more relaxed for a household kitchen.

Technical Capabilities:
• Operating Voltage: 5V (Essential for the internal heater).
• Power Consumption: ~150mA (Ensure your power supply can handle the heater's current draw).
• Stability: Once the "burn-in" and preheat phases are complete, the sensor provides a very stable baseline for continuous monitoring.

Best For:
The MQ-4 is the go-to component for domestic gas leakage alarms, industrial methane monitoring, CNG vehicle safety systems, and smart city environmental sensors.