Description
Reviews
| Brand | - |
| Category | Robotics / STEM Teaching Tools / Sensors |
| Origin | - |
| Model Number | MQ-2-135-3-7-9 |
| Detection Gases | Smoke, LPG, Alcohol, Hydrogen, CO |
| Operating Voltage | 5V DC |
| Output Signal | Analog and Digital (TTL) |
| Preheat Time | 24-48 Hours |
| Sensitivity Adjustment | Potentiometer Included |
| Interface Type | 3-Pin Header (VCC, GND, OUT) |
| Dimensions | 32mm x 20mm x 15mm |
| Compatibility | Arduino, Raspberry Pi, ESP32 |
| Mounting Style | Through-hole with Standoffs |
Anonymous
Mar 29, 2026
Rating: 5/5
Reliable gas detection
Integrated this into my smart home system to monitor the garage for fuel leaks. It picks up hydrogen and combustible gases quickly. The digital output pin is a nice feature for simple alarm triggers.
Anonymous
Mar 18, 2026
Rating: 5/5
Great addition to my greenhouse monitor
Using this to monitor air quality and potential fermentation gases in my composting area. It responds well to changes in air composition. The build quality feels sturdy enough for long-term use.
Anonymous
Mar 15, 2026
Rating: 4/5
Good sensitivity, needs patience
The sensor is very sensitive to alcohol and smoke as advertised. Just remember to let it warm up for at least 24 hours before calibrating, or your readings will be all over the place. Once calibrated, it's solid.
Anonymous
Mar 14, 2026
Rating: 4/5
Works well but gets hot
Functionality is top-notch for the cost. Be aware that the heating element inside gets quite hot during operation, which is normal for this type of sensor, but ensure your enclosure has ventilation.
Anonymous
Mar 06, 2026
Rating: 5/5
Excellent for learning embedded systems
Bought this for a university project on air quality monitoring. The documentation provided by the seller was helpful, and the potentiometer makes threshold adjustment very easy. Highly recommended for students.
Anonymous
Mar 04, 2026
Rating: 5/5
Perfect for home safety projects
This sensor module works flawlessly with my Arduino setup. The analog output is stable after the initial preheat time, and detecting smoke from a simple test was immediate. Great value for the price.
Q: Does this module require an external library to work with Arduino?
A: No external library is strictly required. You can read the analog value using the standard analogRead() function. However, many users find community libraries helpful for calibration and unit conversion.
Q: Can this detect natural gas specifically?
A: Yes, the MQ-2 sensor is sensitive to methane and other combustible gases found in natural gas, though it is not specific to one gas type and reacts to a range of combustible vapors.
Q: Is the digital output adjustable?
A: Yes, there is a blue potentiometer on the board that allows you to adjust the sensitivity threshold for the digital output pin (DO). Turning it changes the point at which the LED lights up and the signal goes low.
Q: What is the exact preheat time needed before accurate readings?
A: For stable and accurate baseline readings, we recommend a preheat time of 24 to 48 hours. Shorter periods may result in fluctuating values as the sensor element stabilizes.
Q: What is the power consumption of this module?
A: The module typically consumes around 150mA to 200mA at 5V due to the internal heating element required for the sensor to operate correctly. Ensure your power supply can handle this load.
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