Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Sensor Type	MQ-3 Semiconductor Gas Sensor
Detectable Gas	Alcohol, Ethanol, Methane
Operating Voltage	5V DC
Output Signal	Analog (AO) and Digital (DO)
Sensitivity Range	0.04mg/L - 4mg/L (Alcohol)
Response Time	< 10 seconds
Recovery Time	< 30 seconds
Heater Voltage	5V ± 0.2V
Load Resistance	200kΩ (Adjustable)
Board Dimensions	32mm x 20mm x 14mm

6 reviews

Anonymous

Mar 30, 2026

Rating: 4/5

Works well but gets hot

Functionality is spot on for detecting alcohol concentration. Note that the heating element gets quite hot during operation, which is normal for this type of sensor, but ensure your enclosure has ventilation. Overall satisfied.

Anonymous

Mar 25, 2026

Rating: 4/5

Good sensitivity, needs warm-up

The sensor is very sensitive to ethanol vapors. Just remember that it needs about 2-3 minutes to warm up before giving accurate readings. Once heated, the response is quick. Documentation could be better, but plenty of tutorials exist online.

Anonymous

Mar 16, 2026

Rating: 3/5

Decent but requires calibration

The sensor works, but don't expect plug-and-play precision out of the box. You must spend time calibrating it in fresh air and then with a known alcohol source to get meaningful data. Good for hobbyists, maybe not for industrial use without extra work.

Anonymous

Mar 12, 2026

Rating: 5/5

Easy to interface with microcontrollers

Connected this to an ESP32 without any issues. The voltage levels are compatible, and the signal is clean. I used it to build a simple safety alarm for a home brewing setup, and it triggers reliably when ethanol levels rise.

Anonymous

Mar 04, 2026

Rating: 5/5

Reliable for classroom kits

We bought ten of these for our robotics club. They are robust and handle student handling well. The dual output (analog and digital) is excellent for teaching different ways to read sensor data with Arduino.

Anonymous

Mar 02, 2026

Rating: 5/5

Perfect for my breathalyzer prototype

This module works exactly as described. The analog output is stable after the initial warm-up period, and the digital threshold potentiometer makes it easy to calibrate for specific alcohol levels. Great value for electronics projects.

5 FAQ

Q: Does this module come with headers soldered?

A: Yes, the module typically comes with the pin headers pre-soldered, ready for immediate use with breadboards or jumper wires.

Q: Is the digital output pin active high or active low?

A: The digital output (DO) state depends on your calibration via the onboard potentiometer. Typically, it goes LOW when the gas concentration exceeds the set threshold and HIGH when it is below the threshold, but this can be inverted by adjusting the comparator settings if your board supports it.

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

A: Under normal operating conditions, the MQ-3 sensor element has a typical lifespan of 1 to 2 years in air. Continuous exposure to high concentrations of corrosive gases may reduce this lifespan.

Q: What is the power consumption of this sensor?

A: The heater inside the sensor consumes approximately 150mW to 200mW at 5V. Please ensure your power supply can provide at least 200mA to maintain stable operation.

Q: Can this detect methane gas as well?

A: While the MQ-3 is primarily optimized for alcohol and ethanol, it does have some cross-sensitivity to methane and other combustible gases. However, for dedicated methane detection, we recommend the MQ-4 or MQ-5 sensors for better accuracy.

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