Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Model Number	MQ-2-3-4-5-6-7-8-9-135
Detection Range	LPG, Propane, Hydrogen, Alcohol, Smoke
Operating Voltage	5V DC
Output Type	Digital DO and Analog AO
Preheat Time	24-48 Hours
Sensitivity Adjustment	Potentiometer Included
Interface	3-Pin Header (VCC, GND, OUT)
Dimensions	32mm x 20mm x 15mm
Compatibility	Arduino, Raspberry Pi, ESP32
Package Contents	1x Sensor Module, 1x Pin Header

6 reviews

Anonymous

Mar 31, 2026

Rating: 3/5

Works but requires calibration

The sensor works, but don't expect plug-and-play precision without tuning. You need to spend time adjusting the potentiometer and writing code to filter out noise. Good for hobbyists, maybe not for critical industrial use without extra processing.

Anonymous

Mar 30, 2026

Rating: 5/5

Perfect for my home safety project

This sensor module worked exactly as described. I connected it to my Arduino Uno and was able to detect smoke from a lit match within seconds after the preheat period. The analog output gives great granularity for logging data.

Anonymous

Mar 14, 2026

Rating: 5/5

Great for learning electronics

Bought this for a university project on air quality monitoring. The documentation online is plentiful, and the potentiometer makes it easy to set the threshold for the digital pin. Highly recommended for beginners.

Anonymous

Mar 11, 2026

Rating: 5/5

Reliable component

I have purchased five of these modules for different prototypes. They are consistent in performance. The PCB quality is decent, and the soldering points are clear. No issues so far.

Anonymous

Mar 07, 2026

Rating: 4/5

Sensitive and responsive

I tested it against alcohol vapor and LPG lighter fluid, and it triggered the alarm circuit immediately. The only downside is the power consumption is slightly higher than expected, but acceptable for a stationary setup.

Anonymous

Mar 05, 2026

Rating: 4/5

Good value but needs patience

The hardware is solid and the price is unbeatable. Just remember that you must let it preheat for at least 24 hours before calibration, or the readings will be all over the place. Once stabilized, it works well.

5 FAQ

Q: How long does the preheat time really need to be?

A: For stable and accurate readings, we recommend a preheat time of 24 to 48 hours. Shorter periods may result in fluctuating baseline values.

Q: Does this module work with 3.3V logic systems like ESP8266?

A: Yes, the digital output is compatible with 3.3V systems, but the sensor heating element requires a stable 5V supply for proper operation. Ensure your power source can provide enough current.

Q: Is the pin header included or do I need to solder it myself?

A: The package includes the pin header strip, but it is not pre-soldered to the board. You will need to solder it yourself to fit your specific breadboard or wiring needs.

Q: What is the current consumption during operation?

A: The heating element typically draws about 150mA to 200mA at 5V. Please ensure your microcontroller or power bank can supply this current continuously.

Q: Can this detect carbon monoxide specifically?

A: While this sensor is sensitive to combustible gases and smoke which often accompany CO, it is not a dedicated Carbon Monoxide sensor. For specific CO detection, please look for the MQ-7 model.

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