Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Model Compatibility	MQ-2, MQ-3, MQ-4, MQ-5, MQ-6, MQ-7, MQ-8, MQ-9, MQ-135
Operating Voltage	5V DC
Output Signal	Digital Switch Output (0 and 1) and Analog Output
Detection Range	Varies by specific sensor type (e.g., LPG, Alcohol, CO, Smoke)
Interface Type	3-Pin Connector (VCC, GND, DO/AO)
Adjustable Sensitivity	Yes, via onboard potentiometer
Indicator LED	Power LED and Digital Switch Output LED
PCB Dimensions	32mm x 20mm x 14mm
Primary Application	Gas leakage detection, safety monitoring, DIY electronics projects
Package Includes	1x Sensor Module Board (Sensor chip pre-soldered)

6 reviews

Anonymous

Mar 31, 2026

Rating: 5/5

Great for learning

Bought this for my university embedded systems class. The documentation online is plentiful, and the analog output allows for detailed data logging. Highly recommend for students.

Anonymous

Mar 29, 2026

Rating: 5/5

Perfect for Arduino Projects

I bought the MQ-2 version for my home safety prototype. It connects easily to my Arduino Uno and the sensitivity adjustment works great. Very responsive to smoke tests.

Anonymous

Mar 26, 2026

Rating: 5/5

Reliable gas detection

Using the MQ-4 for natural gas monitoring in my workshop. The digital output triggers my buzzer alarm instantly when I test it with a lighter nearby. Solid build quality.

Anonymous

Mar 24, 2026

Rating: 5/5

Bulk buy success

Purchased multiple units for our robotics club. All modules arrived in good condition and performed consistently across different microcontrollers including ESP32 and Raspberry Pi.

Anonymous

Mar 24, 2026

Rating: 4/5

Works well, gets hot

The sensor functions perfectly for detecting alcohol vapors with the MQ-3. Note that the heating element gets quite warm during operation, which is normal for this type of sensor. Ensure proper ventilation in your enclosure.

Anonymous

Mar 07, 2026

Rating: 4/5

Good value but needs calibration

The module works as described. Just remember these sensors need a burn-in time of about 24-48 hours before they give stable readings. Once calibrated, the MQ-135 detects air quality changes well.

5 FAQ

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

A: Yes, the digital output is compatible. However, the module itself requires a 5V power supply for the heater. You may need a voltage divider or level shifter if connecting the DO pin directly to a 3.3V GPIO without internal tolerance.

Q: Can I detect Carbon Monoxide with the MQ-2 sensor?

A: No, the MQ-2 is primarily designed for LPG, i-butane, propane, methane, alcohol, hydrogen, and smoke. For Carbon Monoxide detection, please select the MQ-7 or MQ-9 model specifically.

Q: Is this sensor waterproof for outdoor use?

A: No, the bare sensor module is not waterproof. If you plan to use it outdoors, you must house it in an IP-rated enclosure with a breathable membrane to allow gas entry while protecting against rain and dust.

Q: How long does the sensor need to warm up before use?

A: For accurate readings, we recommend powering the sensor for at least 24 to 48 hours initially to burn in the heating element. After the initial burn-in, a warm-up period of 1-2 minutes before each reading session is sufficient.

Q: What is the difference between the DO and AO pins?

A: AO (Analog Output) provides a continuous voltage signal proportional to the gas concentration, allowing you to measure levels. DO (Digital Output) acts as a switch; it goes HIGH or LOW when the gas concentration exceeds the threshold set by the potentiometer.

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