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 (DO) and Analog (AO)
Heating Voltage	5.0V ± 0.2V
Load Resistance	200kΩ
Heater Resistance	33Ω ± 10%
Sensing Range	0.04mg/L to 4mg/L
Response Time	< 10 seconds
Board Dimensions	32mm x 20mm x 14mm

6 reviews

Anonymous

Mar 30, 2026

Rating: 5/5

Great starter sensor

As someone new to electronics, I found this easy to wire up. Plenty of tutorials online helped me get the code running. It lights up the LED immediately when exposed to hand sanitizer vapor.

Anonymous

Mar 15, 2026

Rating: 3/5

Works but gets hot

The sensor detects alcohol as advertised, but the heating element gets quite hot during operation. Make sure your enclosure has ventilation. Otherwise, it functions correctly for basic detection tasks.

Anonymous

Mar 14, 2026

Rating: 5/5

Reliable and Affordable

I bought three of these for a breathalyzer prototype. All three performed consistently. The digital output threshold is adjustable via the potentiometer, which is a nice feature.

Anonymous

Mar 13, 2026

Rating: 4/5

Good sensitivity, needs calibration

The module arrived quickly and looks well-soldered. It does require some time to heat up before giving accurate readings, which is normal for this type of sensor. Once calibrated, it performs well.

Anonymous

Mar 08, 2026

Rating: 5/5

Perfect for Arduino Projects

This sensor works flawlessly with my Arduino Uno. The analog output is stable after the initial warm-up period, and detecting alcohol vapor is very responsive. Great value for hobbyists.

Anonymous

Mar 01, 2026

Rating: 4/5

Solid performance for the price

No complaints here. It's a standard MQ-3 module. The pins are clearly labeled, and the PCB quality seems decent. Just remember it consumes more power than typical logic sensors due to the heater.

5 FAQ

Q: How long does it take for the sensor to warm up?

A: Typically, MQ series gas sensors require a preheat time of about 24 to 48 hours for stable long-term usage, but for basic testing, you will see reactive results within 1 to 2 minutes of powering on.

Q: Does this module work with 3.3V microcontrollers like ESP32?

A: The sensor heater requires 5V to operate correctly. While the logic output might work with 3.3V, we recommend powering the VCC pin with 5V and using a voltage divider or level shifter for the signal pins if connecting to a 3.3V MCU.

Q: What is the purpose of the blue potentiometer on the board?

A: The blue potentiometer adjusts the sensitivity threshold for the Digital Output (DO). Turning it changes the point at which the DO LED turns on and the signal pin goes low/high.

Q: Is there a library available for this sensor?

A: Since this is an analog/digital hardware sensor, it doesn't need a specific driver library. You simply read the analog value using the standard 'analogRead()' function in Arduino or similar commands in other platforms.

Q: Can this detect cigarette smoke?

A: While it may react slightly to smoke, the MQ-3 is specifically tuned for alcohol and ethanol. For smoke detection, we recommend the MQ-2 or MQ-7 sensors which are optimized for combustible gases and smoke.

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