Description
Reviews
| Brand | - |
| Category | Robotics / STEM Teaching Tools / Sensors |
| Origin | - |
| Package Contents | 9x Gas Sensor Modules (MQ-2, MQ-3, MQ-4, MQ-5, MQ-6, MQ-7, MQ-8, MQ-9, MQ-135) |
| Operating Voltage | 5V DC |
| Interface Type | Analog Output (AO) and Digital Output (DO) |
| Heater Voltage | 5.0V ± 0.2V |
| Load Resistance | Adjustable via onboard potentiometer |
| PCB Dimensions | 32mm x 20mm per module |
| Mounting Holes | 4x 3mm diameter holes for easy installation |
| Compatibility | Arduino, Raspberry Pi, ESP32, STM32, and other 5V microcontrollers |
| Pre-heat Time | Approximately 24-48 hours for initial stabilization |
| Application Range | Air quality monitoring, leak detection, and hobbyist electronics projects |
Anonymous
Mar 28, 2026
Rating: 5/5
Great for environmental monitoring
I am using the MQ-135 and MQ-4 in my greenhouse automation system. They detect changes in CO2 and methane reliably. The form factor is compact and fits easily into my custom enclosures.
Anonymous
Mar 27, 2026
Rating: 5/5
Perfect starter kit for gas sensing
This kit includes every common MQ sensor you need for prototyping. The modules are well-soldered and the potentiometers work smoothly for adjusting sensitivity. Great value for the price.
Anonymous
Mar 24, 2026
Rating: 4/5
Solid modules for Arduino projects
Integration with my Arduino Uno was plug-and-play. The digital output pins are very responsive. I deducted one star because the pin headers were slightly loose on two of the modules, but nothing a little solder couldn't fix.
Anonymous
Mar 19, 2026
Rating: 4/5
Good quality, just remember to pre-heat
The sensors work as expected once they have been burned in for a day or two. Don't expect accurate readings immediately out of the box. The documentation could be better, but there are plenty of online tutorials.
Anonymous
Mar 18, 2026
Rating: 5/5
Excellent variety in one pack
Buying these individually costs much more. Having the MQ-135 for air quality and the MQ-2 for smoke in the same package allowed me to build a comprehensive home safety monitor quickly.
Anonymous
Mar 15, 2026
Rating: 5/5
Best purchase for learning sensors
As a beginner, this kit gave me the chance to experiment with different gases without breaking the bank. The analog readings are consistent, and I learned a lot about calibration curves.
Q: How long does the burn-in period take?
A: For stable and reliable readings, we recommend powering the sensors continuously for 24 to 48 hours before taking critical measurements. This stabilizes the internal heating element and sensing material.
Q: Is the MQ-9 suitable for detecting Carbon Monoxide?
A: Yes, the MQ-9 is specifically designed to detect Carbon Monoxide (CO) as well as combustible gases like LPG and propane. It is one of the primary sensors included for safety applications.
Q: Do these sensors provide calibrated ppm readings out of the box?
A: No, these are raw sensor modules. They output analog voltage proportional to gas concentration. You must perform your own calibration using known gas sources or reference data to convert voltage to specific ppm values.
Q: What is the return policy if a sensor arrives defective?
A: We offer a 30-day replacement guarantee for any manufacturing defects. Please contact our support team with your order number and a description of the issue, and we will ship a replacement immediately.
Q: Can I power these directly from a 3.3V microcontroller like ESP8266?
A: The heater element requires 5V to operate correctly. While the logic output might work at 3.3V, we strongly recommend powering the VCC pin with 5V. If your MCU is 3.3V only, use a level shifter for the data pins or a separate 5V supply for the sensor.
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