MQ-5 Natural/ LPG Gas Sensor Module

The MQ-5 gas sensor module detects LPG, natural gas, methane (CH₄), hydrogen (H₂) and carbon monoxide (CO). It gives both an analog voltage (AO) proportional to gas level and a digital TTL output (DO) that flips when a user-set threshold is reached — perfect for Arduino and other microcontroller projects.

Key Features

• Detects LPG, natural gas, CH₄, H₂ and CO
• Fast response and stable output
• Dual outputs: AO (analog) and DO (digital)
• Adjustable threshold via onboard potentiometer
• Simple drive circuit; easy to integrate into hobby projects
• Long working life when used per datasheet recommendations

Quick Specifications (at a glance)

• Working Voltage: 5V (4.9V - 5.1V)
• Heater Resistance: ~31 Ω (±10%)
• Sensing Resistance Range: 10 kΩ – 60 kΩ
• Typical Detection Range: 200 – 10,000 ppm (depends on gas)
• Power: sensor heater consumption ~0.5–800 mW (module dependent)

Pinout / Connections

• Vcc: +5V power
• GND: Ground
• AO: Analog output (read with ADC, e.g. Arduino A0)
• DO: Digital output (HIGH/LOW depending on threshold)

How it works?

The MQ-5 sensor element changes resistance when it detects target gases. The module converts that change into an analog voltage (AO). The onboard potentiometer sets a threshold that controls the digital output (DO). Use AO for concentration relative readings and DO for simple alarm/trigger logic.

Basic Wiring

1. Connect Vcc → Arduino 5V
2. Connect GND → Arduino GND
3. Connect AO → Arduino analog pin (example: A0)
4. Connect DO → Arduino digital pin (example: 2) — optional

Calibration & Practical Tips

• Warm-up: Let the sensor warm up for 1–10 minutes (or longer) after power-up — readings are unstable while cold.
• Threshold: Use the potentiometer to set the DO trigger for the concentration level you want.
• AO readings: Analog values are relative — to estimate ppm you need calibration with known gas concentrations.
• Placement: Install the sensor where gas could reasonably accumulate (low for LPG, higher for lighter gases), and avoid strong drafts that dilute readings.
• Power stability: Use a stable 5V supply; noisy supply lines affect readings.

Common Applications

• Home gas-leak detection (LPG / city gas)
• Gas leak alarms for kitchens or appliances
• DIY safety and monitoring projects with microcontrollers
• Small-scale environmental monitoring (relative measurements)

Safety Notes

• This sensor is for detection/alerting and hobby use. It is not a certified replacement for commercial safety equipment.
• Always test and verify with proper calibration and follow local safety regulations for gas detection.

Tip: For more precise results combine the MQ-5 analog reading with calibration data or use a professional, certified gas detector for life-safety applications.