Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Model Number	MQ-3
Detection Target	Alcohol, Ethanol, Flammable Gases
Operating Voltage	5V DC
Output Signal	Analog (AO) and Digital (DO)
Sensitivity Range	0.04mg/L to 4mg/L (Alcohol)
Response Time	< 10 seconds
Recovery Time	< 30 seconds
Heater Voltage	5.0V ± 0.2V
Load Resistance	Adjustable via Potentiometer
Interface Type	3-Pin Header (VCC, GND, OUT)

6 reviews

Anonymous

Mar 30, 2026

Rating: 4/5

Good value but needs calibration

The module is well-built and the digital output threshold is adjustable. Just remember it takes a few minutes to heat up before giving accurate readings. Solid choice for hobby projects.

Anonymous

Mar 27, 2026

Rating: 5/5

Reliable and easy to integrate

I've used several gas sensors, and this MQ-3 is one of the most consistent. The pinout is standard, making it easy to wire into existing PCBs. Highly recommended for students.

Anonymous

Mar 24, 2026

Rating: 5/5

Excellent sensitivity

Very impressed with how sensitive this probe is. Even small amounts of alcohol vapor trigger the digital output when calibrated correctly. Fast shipping too.

Anonymous

Mar 13, 2026

Rating: 3/5

Decent but requires warm-up

The sensor functions well once heated, but you must account for the 2-3 minute warm-up time in your code logic. Otherwise, initial readings are erratic. Good for the price.

Anonymous

Mar 13, 2026

Rating: 5/5

Perfect for my breathalyzer prototype

This sensor works exactly as described. I connected it to an Arduino and the analog readings were stable after the initial warm-up period. Great sensitivity for ethanol detection.

Anonymous

Mar 08, 2026

Rating: 4/5

Works well for alcohol detection

Successfully used this to detect hand sanitizer vapors in a smart dispenser project. It reacts quickly. The only downside is the power consumption due to the heating element.

5 FAQ

Q: Can this detect methane or propane?

A: While the MQ-3 is optimized for alcohol and ethanol, it may show some reactivity to other flammable gases. However, for methane or propane, we recommend the MQ-4 or MQ-5 models for better accuracy.

Q: What is the current draw during operation?

A: The heater inside the sensor typically draws about 150mA to 200mA at 5V. Please ensure your microcontroller or power supply can handle this load.

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

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

Q: Is a library available for Arduino?

A: Yes, there are several open-source libraries available on the Arduino Library Manager specifically for MQ series sensors that simplify reading and calibration.

Q: Does this module output a simple high/low signal or an analog value?

A: It provides both. The DO pin gives a digital high/low signal based on your potentiometer setting, while the AO pin provides a variable analog voltage proportional to gas concentration.

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