MQ-6 Isobutane & Propane Gas Sensor Module - LPG Leak Detector

Specifications

• Target Gases: Isobutane, Propane, LPG (Liquefied Petroleum Gas).

• Detection Range: 200ppm – 10,000ppm.

• Operating Voltage: 5V DC ±0.1V.

• Heater Consumption: ~150mA (750mW).

• Output Format:

  • Analogue (A0): Voltage increases linearly with gas concentration.

  • Digital (D0): Logic High/Low trigger based on potentiometer setting.

• Response Time: < 10s.

• Dimensions: 32mm x 20mm x 22mm.

Compatibility & Platform Support

• Arduino (Uno/Nano/Mega): Directly Compatible. The 5V logic matches perfectly.

• ESP32 / ESP8266: ⚠️ Caution Required. The Analog output typically ranges from 0 to 4V. You MUST use a voltage divider (e.g., 10kΩ & 20kΩ resistors) to drop the signal below 3.3V to avoid damaging the ESP32 ADC.

• Raspberry Pi: ⚠️ Requires ADC. The Pi cannot read analogue voltages. Use an external ADC chip (MCP3008) or use the Digital (D0) pin for a simple "Leak / No Leak" alarm.

Key Applications & Projects

• Smart Camping Monitor: Build a battery-operated leak detector for your camping gear or caravan.

• LPG Cylinder Weighing Scale: Combine this with a Load Cell to monitor both the weight (gas left) and leaks (safety) of your home cylinder.

• Industrial HVAC Safety: Monitor propane-fueled heating systems for leakages.

• Robotic Sniffer: Mount on a mobile robot to trace gas plumes to their source.

Project Evolution

• Prerequisites: You should know how to use analogRead() and map values in code.

• The Upgrade: Integrate this with an LCD Display (16x2) to show real-time "Safety Levels" (Safe/Warning/Danger) instead of just a buzzer alarm.

• Effort Level: Intermediate. The hardware setup is plug-and-play, but interpreting the analogue data requires some testing.

Virtual Technician: Wiring & Safety ⚠️

• VCC: Connect to 5V (Stable source required).

• GND: Connect to Common Ground.

• D0: Connect to Digital Pin (for alarm trigger).

• A0: Connect to Analogue Pin (for measurement).

• Heater Warning: The sensor feels hot (~40°C) during operation. This is normal. Do not touch the mesh while powered.

Accessories

• Included in the Box: 1 x MQ-6 Isobutane/Propane Gas Sensor Module

• Required Accessories (Not Included):

  • Controller: Arduino Uno or ESP32.

  • Wires: Female-to-Male Jumper Wires.

  • Power: 5V 1A Adapter (USB power is okay for testing, but wall power is better for 24/7 use).

  • Alert: Active Buzzer or Relay Module.

Frequently Asked Questions (FAQ)

• What is the main difference between MQ-6 and MQ-2? MQ-6 is highly sensitive to Isobutane and Propane (Bottled Gas). MQ-2 is a general-purpose sensor for Smoke, Hydrogen, and LPG. MQ-6 is "cleaner" (less noise) for gas leak detection.
• Does it detect Natural Gas (Methane)? It has some sensitivity to Methane, but MQ-4 is much better for that. Use MQ-6 for Propane/LPG.
• Why is the sensor getting hot? It contains a heating element that must reach ~40°C to activate the chemical sensing layer. This is by design.
• How long does it take to stabilize? On first use, run it for 24 hours. For daily use, give it 2-5 minutes to warm up before trusting the reading.
• Can I run it on a 3.7V LiPo battery? No. The heater needs 5V. At 3.7V, it won't get hot enough to detect gas accurately. You need a "Boost Converter" to step 3.7V up to 5V.
• How do I calibrate the alarm threshold? Turn the blue potentiometer on the back. Clockwise increases sensitivity (triggers earlier). Counter-clockwise decreases it.
• Is it waterproof? No. Water will ruin the sensor. Keep it dry.
• What is the range in PPM? Approximately 200ppm to 10,000ppm.
• Can it detect alcohol? It has very low sensitivity to alcohol compared to MQ-3, but strong alcohol fumes might still cause a small reading.
• Why is my reading fluctuating? Unstable power supply is the #1 cause. Ensure you have a solid 5V. Air currents (wind) blowing on the sensor can also cause noise.
• How do I clean it? Do not use chemicals! If dusty, use a dry air blower. Solvents can poison the sensor permanently.
• What is the lifespan? Typical lifespan is 4-5 years in clean air.
• Can I use it for fire detection? It is not optimised for smoke particles. Use a Flame Sensor or MQ-2 for fire.
• Is the output linear? No, gas sensors have a logarithmic response. You need to use log() functions in your code for accurate PPM calculation.
• Can I use this with a Raspberry Pi Pico? Yes, but like the ESP32, the Pico is 3.3V. Use a voltage divider on the Analog pin!
• Does it work in cold temperatures? Yes, but extreme cold can affect the heater temperature. Re-calibration might be needed in winter.
• What happens if I reverse polarity? The module usually does not have reverse protection. It will likely damage the components.
• Can I extend the wires? Yes, but for Analog signals, keep wires short (<1m) or use shielded cable to avoid interference.
• Why does the LED stay on? The sensitivity might be set too high. Turn the pot counter-clockwise until it turns off.
• Is this sensor certified for industrial safety? No, this is a development/prototyping module.