Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Model Number	MQ-3
Detection Gas	Alcohol, Ethanol, Methane
Operating Voltage	5V DC
Output Type	Digital (TTL) and Analog
Sensitivity Range	0.04mg/L - 4mg/L
Preheat Time	20+ seconds
Load Resistance	200kΩ
Heater Resistance	33Ω ± 10%
Dimensions	32mm x 20mm x 14mm
Application	Breathalyzer, Gas Leak Detection

6 reviews

Anonymous

Mar 24, 2026

Rating: 3/5

Decent but sensitive to humidity

The sensor works well for its intended purpose, but I noticed the readings fluctuate slightly in high humidity environments. You might need to add a humidity compensation algorithm in your code for precise measurements.

Anonymous

Mar 19, 2026

Rating: 4/5

Good value but needs calibration

The build quality is solid for the price. Just remember that it requires a warm-up period of about 20 seconds before the readings stabilize. Once calibrated, it detects alcohol vapor very reliably.

Anonymous

Mar 18, 2026

Rating: 4/5

Works well, gets hot

The sensor functions perfectly for detecting ethanol concentrations. Note that the heating element gets quite warm during operation, which is normal for this type of semiconductor sensor. Ensure proper ventilation in your enclosure.

Anonymous

Mar 11, 2026

Rating: 5/5

Reliable and consistent

We purchased ten of these for our robotics club. All units performed consistently. The analog output allows for granular data logging, which is great for our analysis software.

Anonymous

Mar 04, 2026

Rating: 5/5

Great for science fair projects

Bought this for a high school science project on air quality. It was easy to interface with Raspberry Pi using an ADC. The sensitivity is impressive for such a small module.

Anonymous

Mar 02, 2026

Rating: 5/5

Perfect for my Arduino project

This sensor module worked exactly as described. I connected it to my Arduino Uno and had readings within minutes. The digital output makes it very easy to set a threshold for an alarm system.

5 FAQ

Q: What is the response time of the sensor?

A: The typical response time is less than 10 seconds once the sensor has completed its initial preheating phase. Recovery time to return to baseline levels is usually under 30 seconds.

Q: Is there a library available for Arduino?

A: Yes, there are several open-source libraries available in the Arduino Library Manager that support MQ series sensors. They simplify the process of reading analog values and converting them to ppm estimates.

Q: Does this work with 3.3V logic systems like ESP32?

A: The module operates at 5V. While the analog output may work with 3.3V systems, the digital TTL output is 5V. We recommend using a logic level converter if connecting the digital pin directly to a 3.3V microcontroller.

Q: How long does the sensor last before needing replacement?

A: Under normal operating conditions, the MQ-3 sensor typically has a lifespan of 1 to 2 years. Continuous exposure to extremely high concentrations of gas may reduce its longevity.

Q: Can this sensor detect pure ethanol or only vapors?

A: This MQ-3 module is designed to detect alcohol vapors in the air, not liquid ethanol directly. It is ideal for breathalyzer applications or detecting gas leaks.

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