Skip to main content
Home / Computer Hardware, Monitors & Peripherals / Smoke Sensor Module MQ-2/3/4/5/6/7/8/9, MQ135, Combustible Gas, Alcohol, Carbon Monoxide Detector

Attributes

Brand -
Category Electronic Components / Maker DIY / Computer Hardware, Monitors & Peripherals
Origin -
Sensor Series MQ-2 / MQ-3 / MQ-4 / MQ-5 / MQ-6 / MQ-7 / MQ-8 / MQ-9 / MQ-135
Operating Voltage 5V DC
Output Type Analog (AO) and Digital TTL (DO)
Comparator IC LM393 Wide Voltage Comparator
Sensing Target Combustible Gas, Alcohol, Smoke, CO, Hydrogen
Preheat Duration 24-48 Hours Recommended for Stability
Operating Temperature -10°C to 50°C
PCB Dimensions 32mm x 20mm x 22mm
Interface Pins VCC, GND, Digital Out, Analog Out
Application DIY Electronics, Prototyping, Education, Robotics

5 reviews

A

Anonymous

Apr 01, 2026

Rating: 4/5

Value for money

Cheaper than local electronics stores and works just as well for hobby projects. Shipping was fast.

A

Anonymous

Mar 26, 2026

Rating: 5/5

Perfect for students

Used in our workshop for teaching sensor interfacing. Students found it easy to integrate with Arduino boards.

A

Anonymous

Mar 05, 2026

Rating: 5/5

Solid build quality

PCB looks professional and soldering points are clear. The header pins were included which was a nice touch.

A

Anonymous

Feb 28, 2026

Rating: 4/5

Good sensitivity

Takes time to warm up as described, but once heated it detects gas changes quickly. Good value for the price.

A

Anonymous

Feb 23, 2026

Rating: 5/5

Works great with ESP32

Connected easily to my ESP32 project. The analog output is smooth and the digital threshold is adjustable via the potentiometer. Great for learning.

5 FAQ

Q: How do I calibrate the sensor?

A: Place the sensor in clean air for the preheat period, then read the baseline analog value to set your threshold.

Q: What is the exact pinout configuration?

A: The pins are labeled on the PCB: VCC for power, GND for ground, DO for digital output, and AO for analog output.

Q: Which model is best for detecting alcohol vapor?

A: The MQ-3 model is specifically optimized for alcohol and ethanol detection compared to the other variants.

Q: Does it work with 3.3V logic microcontrollers?

A: Yes, the digital output is compatible, but we recommend powering the module with 5V for proper heater operation.

Q: Is this certified for home safety alarm systems?

A: No, this module is designed for educational and prototyping purposes only. It is not certified for life-safety applications.

Explore your interests

View More
All Categories
Best Seller (30)
New List (30)
Front Wiper Arm Assembly for Citroën C-Elysée, Xsara Picasso, Peugeot 307/301

Front Wiper Arm Assembly for Citroën C-Elysée, Xsara Picasso, Peugeot 307/301

$35.00

Underbite Corrector Case - Portable Magnetic Lanyard Storage Box for Frankel Appliance and TB Palatal Expander

Underbite Corrector Case - Portable Magnetic Lanyard Storage Box for Frankel Appliance and TB Palatal Expander

$22.70

Car Tire Stone Removal Tool, Multi-Function Hook for Picking and Extracting Stones from Treads

Car Tire Stone Removal Tool, Multi-Function Hook for Picking and Extracting Stones from Treads

$6.43

Outdoor Lamp Stand for Camping, Lantern Holder Pole for Street Vending and Night Fishing

Outdoor Lamp Stand for Camping, Lantern Holder Pole for Street Vending and Night Fishing

$13.89

Waste Removal and Paper Stacking Machine, Automatic Paper Collection and Counting Receiver for Carton Printing Equipment, Carton Factory Machinery

Waste Removal and Paper Stacking Machine, Automatic Paper Collection and Counting Receiver for Carton Printing Equipment, Carton Factory Machinery

$6,400.00

Sheepskin Baby Rattle - Chewable Traditional Handmade Shaker Bell, Intangible Cultural Heritage Essential for Newborn Care

Sheepskin Baby Rattle - Chewable Traditional Handmade Shaker Bell, Intangible Cultural Heritage Essential for Newborn Care

$57.00

Zhizhi Study Room 'Small Pot Sky' Brush Washer - Traditional Handmade Glass with Lost-Wax Method, Silk Luster, Double-Compartment Water Vessel

Zhizhi Study Room 'Small Pot Sky' Brush Washer - Traditional Handmade Glass with Lost-Wax Method, Silk Luster, Double-Compartment Water Vessel

$457.00

Zao Boshi Insulated Food Cart - Programmable Banquet Warmer for Buns, Breakfast Items, and Hotel Dry/Wet Dishes

Zao Boshi Insulated Food Cart - Programmable Banquet Warmer for Buns, Breakfast Items, and Hotel Dry/Wet Dishes

$11,566.00

Lichuan JK [Blood Oath] - Original Authentic Japanese Dark Style Embroidered Sailor Suit - Spring/Autumn Set

Lichuan JK [Blood Oath] - Original Authentic Japanese Dark Style Embroidered Sailor Suit - Spring/Autumn Set

$59.00

Sink Storage Rack Stainless Steel No-Drill Kitchen Sponge Steel Wool Cloth Pot Lid Organizer Wall-Mounted Drain Rack

Sink Storage Rack Stainless Steel No-Drill Kitchen Sponge Steel Wool Cloth Pot Lid Organizer Wall-Mounted Drain Rack

$4.93

Sketch Blending Stump Set for Artists - Detail Highlight and Shadow Smudging Tools with Replacement Tips

Sketch Blending Stump Set for Artists - Detail Highlight and Shadow Smudging Tools with Replacement Tips

$14.80

Softening Agent for Board Arcs Melamine Softener Eco-Friendly Board Paint-Free Board Whole House Customization Arc Softener

Softening Agent for Board Arcs Melamine Softener Eco-Friendly Board Paint-Free Board Whole House Customization Arc Softener

$9.30

Car Tire Stone Removal Tool - Hook Picker for Cleaning Pebbles from Vehicle Treads

Car Tire Stone Removal Tool - Hook Picker for Cleaning Pebbles from Vehicle Treads

$3.90

Electrical Box with PLC System and VFD for Fans and Pumps

Electrical Box with PLC System and VFD for Fans and Pumps

$2,519.00

Zunjue Watercolor Sketchbook 300g Fabric-Covered Journal – Portable Acrylic Marker Book, 100% Cotton Flip-Style Concertina Drawing Paper

Zunjue Watercolor Sketchbook 300g Fabric-Covered Journal – Portable Acrylic Marker Book, 100% Cotton Flip-Style Concertina Drawing Paper

$13.70

French Imported Arches Watercolor Paper, Handmade Cotton Pulp 300g Full/Half/4K/8K/16K/32K Rough/Medium/Fine Grain, 185g Cotton Pulp for Postcards and Watercolor Books

French Imported Arches Watercolor Paper, Handmade Cotton Pulp 300g Full/Half/4K/8K/16K/32K Rough/Medium/Fine Grain, 185g Cotton Pulp for Postcards and Watercolor Books

$20.80

[Official Authentic] Zichao Bear Wanda Cinema Popcorn Acrylic Keychain Plush Doll Cute Toy

[Official Authentic] Zichao Bear Wanda Cinema Popcorn Acrylic Keychain Plush Doll Cute Toy

$25.40

Heidelberg Printing Press Automatic Blanket Wash Cloth - Non-Woven Cleaning Fabric, 500m Roll

Heidelberg Printing Press Automatic Blanket Wash Cloth - Non-Woven Cleaning Fabric, 500m Roll

$3,185.00

Bucket Pack Natural Wood Colored Pencils Water-Soluble for Kids Coloring and Doodling

Bucket Pack Natural Wood Colored Pencils Water-Soluble for Kids Coloring and Doodling

$6.65

Chunfei Grocery Store Yunm'an GR02 Gravel Bike - Thru-Axle Disc Brake, Lightweight Touring with Multiple Rack Mounts

Chunfei Grocery Store Yunm'an GR02 Gravel Bike - Thru-Axle Disc Brake, Lightweight Touring with Multiple Rack Mounts

$6,444.00

Variable Frequency Drive Power Board ZPOW-591 for ACS880

Variable Frequency Drive Power Board ZPOW-591 for ACS880

$2,200.00

Professional Sketching Eraser Kit - Blending Stumps, Sponges, and Paper Tortillons for Highlight & Shadow Correction

Professional Sketching Eraser Kit - Blending Stumps, Sponges, and Paper Tortillons for Highlight & Shadow Correction

$3.90

Weighted Water Bag with Handle, Thickened PV Mesh Gravity Ballast for Banner Stand Fixation (8KG)

Weighted Water Bag with Handle, Thickened PV Mesh Gravity Ballast for Banner Stand Fixation (8KG)

$35.10

Ultra-Fine Purification Lint-Free Cloth Cleaning Cloth Lens Wipe High Quality 0730 Water-Absorbing Dust Removal UV Nozzle 100 Sheets

Ultra-Fine Purification Lint-Free Cloth Cleaning Cloth Lens Wipe High Quality 0730 Water-Absorbing Dust Removal UV Nozzle 100 Sheets

$96.00

Wen Zhengming Small Regular Script Calligraphy Cards: Li Sao Jing, Thousand Character Classic, Qin Fu, Cao Tang Shi Zhi, Qing Jing Jing, Record of the Drunken Pavilion, Red Cliff Ode

Wen Zhengming Small Regular Script Calligraphy Cards: Li Sao Jing, Thousand Character Classic, Qin Fu, Cao Tang Shi Zhi, Qing Jing Jing, Record of the Drunken Pavilion, Red Cliff Ode

$59.00

Zhizhi Manshu Zhao Mengfu Small Regular Script Collection of Ancient Classics (Vol. 1) - Calligraphy Copybook, Brush Writing Cards, Foldable Practice Cards

Zhizhi Manshu Zhao Mengfu Small Regular Script Collection of Ancient Classics (Vol. 1) - Calligraphy Copybook, Brush Writing Cards, Foldable Practice Cards

$49.00

Language of Drums Motion Path Set - Essential Creativity and Rhythm Teaching Material for Drum Kits and Jazz Drums

Language of Drums Motion Path Set - Essential Creativity and Rhythm Teaching Material for Drum Kits and Jazz Drums

$59.14

onlycook Sink Drain Basket, Faucet-Mounted Food Residue Separator and Washing Strainer - 1 Pack

onlycook Sink Drain Basket, Faucet-Mounted Food Residue Separator and Washing Strainer - 1 Pack

$14.10

Heavy-Duty Wiper Arms and Blades for Trucks and Agricultural Vehicles - Universal Replacement Wiper Rubber Strips

Heavy-Duty Wiper Arms and Blades for Trucks and Agricultural Vehicles - Universal Replacement Wiper Rubber Strips

$5.50

Bus Adapter FEPL-02 for ABB Variable Frequency Drive

Bus Adapter FEPL-02 for ABB Variable Frequency Drive

$1,230.00