Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Model Number	MQ-3
Detection Target	Alcohol, Ethanol, Methane
Input Voltage	5V DC
Output Signal	Analog (AO) and Digital (DO)
Preheat Time	20 seconds minimum
Sensitivity Adjustment	Potentiometer included
Operating Temperature	-10°C to 50°C
Interface Type	3-Pin Header
Compatible Boards	Arduino, Raspberry Pi, ESP32
Package Contents	1x MQ-3 Sensor Module

6 reviews

Anonymous

Mar 31, 2026

Rating: 4/5

Great for learning

Bought this for a university project on gas detection. It's very sensitive, sometimes too much so, but that shows it works. Just ensure you have a clean air environment for baseline calibration.

Anonymous

Mar 22, 2026

Rating: 4/5

Good sensitivity, needs calibration

The module is responsive to alcohol vapors. You definitely need to spend time calibrating the potentiometer to get the digital trigger point right for your specific application. Otherwise, solid hardware.

Anonymous

Mar 17, 2026

Rating: 5/5

Perfect for my breathalyzer prototype

This sensor works exactly as described. The analog output is stable after the initial warm-up period. I connected it to an Arduino Uno and had readings within minutes. Great value for the price.

Anonymous

Mar 13, 2026

Rating: 5/5

Reliable and affordable

I've purchased three of these now for different builds. Consistency between units is good. The heating element gets quite hot, which is normal for this type of sensor, so mount it carefully.

Anonymous

Mar 08, 2026

Rating: 5/5

Easy to integrate

Plug and play with standard microcontrollers. The pinout is clearly marked on the PCB. I used this for a safety project to detect fuel leaks and it performed well during testing.

Anonymous

Mar 06, 2026

Rating: 3/5

Works but slow response

The sensor detects alcohol fine, but the recovery time back to baseline is slower than I expected. Make sure to account for this delay in your code logic. Good for static measurements, less ideal for rapid cycling.

5 FAQ

Q: How long does the sensor need to warm up before taking accurate readings?

A: For best results, allow the sensor to preheat for at least 20 to 30 seconds. For maximum stability and accuracy, leaving it powered on for 24 hours initially is often recommended by the manufacturer.

Q: Does this module output 3.3V or 5V logic levels?

A: The module operates on 5V input. The digital output (DO) typically swings close to the input voltage (5V). If connecting to a 3.3V board like an ESP32, a voltage divider or level shifter is recommended for the DO pin.

Q: What is the current consumption of this module?

A: The heating element consumes approximately 150mA to 200mA at 5V. Ensure your power supply or microcontroller USB port can handle this load, especially if powering multiple sensors simultaneously.

Q: Is the potentiometer for adjusting sensitivity or threshold?

A: The onboard potentiometer adjusts the threshold for the Digital Output (DO) pin. Turning it changes the concentration level at which the DO pin switches from HIGH to LOW. It does not affect the Analog Output (AO) value directly.

Q: Can this detect pure ethanol only or mixed alcohol vapors?

A: The MQ-3 is primarily sensitive to alcohol and ethanol but also has some cross-sensitivity to other combustible gases like methane and propane. It is best suited for general alcohol detection rather than distinguishing specific chemical compounds.

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