Skip to main content
Home / Sensors / MQ-135 Air Quality Detection Sensor Module - High-Sensitivity Probe for Smoke and Harmful Gas Alarm

Attributes

Brand -
Category Robotics / STEM Teaching Tools / Sensors
Origin -
Sensor Type MQ-135 Semiconductor Gas Sensor
Detection Gases Ammonia, Sulfide, Benzene, Smoke, CO2
Operating Voltage 5V DC
Output Signal Analog (AO) and Digital (DO)
Preheat Time 24-48 Hours for Stability
Interface 3-Pin Header (VCC, GND, OUT)
PCB Dimensions 32mm x 20mm
Adjustable Sensitivity Yes, via Onboard Potentiometer
Compatibility Arduino, Raspberry Pi, ESP32, STM32
Package Includes 1x MQ-135 Module, 1x Pin Header Set

6 reviews

A

Anonymous

Mar 30, 2026

Rating: 5/5

Excellent for learning electronics

Bought this for a university project on environmental monitoring. The documentation online is plentiful, and the hardware is robust. It easily interfaces with standard microcontrollers.

A

Anonymous

Mar 26, 2026

Rating: 5/5

Perfect for my smart home project

This sensor works flawlessly with my Arduino setup. The analog output is stable after the initial preheat period, and it detects smoke from a distance effectively. Great value for the price.

A

Anonymous

Mar 23, 2026

Rating: 4/5

Good sensitivity, needs calibration

The module is responsive to changes in air quality. I had to spend some time calibrating the potentiometer to get the digital trigger just right for my greenhouse ventilation system, but once set, it works well.

A

Anonymous

Mar 22, 2026

Rating: 5/5

Reliable alarm trigger

I integrated this into a workshop safety alarm. It reliably triggers the buzzer when soldering fumes are present. The digital output makes integration very simple without complex coding.

A

Anonymous

Mar 01, 2026

Rating: 4/5

Solid build quality

The PCB looks clean and the soldering points are solid. It took about a day to stabilize readings as recommended in the datasheet. Happy with the purchase for prototyping purposes.

A

Anonymous

Mar 01, 2026

Rating: 3/5

Works but gets hot

The sensor functions as described and detects gases accurately. However, the heating element gets quite hot during operation, so ensure you have adequate spacing in your enclosure. Otherwise, no complaints.

5 FAQ

Q: How do I adjust the sensitivity threshold?

A: There is a blue potentiometer on the back of the PCB. Rotate it clockwise to increase sensitivity (lower threshold) or counter-clockwise to decrease it. Test with a gas source while monitoring the DO LED.

Q: Does this module come with the connecting wires?

A: No, the package includes the sensor module and pin headers, but connecting wires are sold separately to allow for custom lengths.

Q: What is the warm-up time required before accurate readings?

A: For stable and accurate baseline readings, we recommend powering the sensor for at least 24 to 48 hours initially. Short-term tests can be done after 10 minutes, but precision will improve over time.

Q: Can this detect Carbon Monoxide specifically?

A: The MQ-135 is sensitive to a broad range of harmful gases including CO, but it is not specific to Carbon Monoxide alone. For dedicated CO detection, a specialized sensor like the MQ-7 is recommended.

Q: Is the output voltage 3.3V or 5V compatible?

A: The module operates on 5V. The analog output scales with the supply voltage. If using a 3.3V microcontroller like ESP32, please use a voltage divider on the analog output pin to prevent damage.

Explore your interests

View More
All Categories
Best Seller (30)
New List (30)
Industrial Large Meat Grinder Fresh Meat Mince Chopper Fruit Vegetable Crusher Meat Grinding and Mixing Integrated Meat Filling Mixer

Industrial Large Meat Grinder Fresh Meat Mince Chopper Fruit Vegetable Crusher Meat Grinding and Mixing Integrated Meat Filling Mixer

$32,030.00

Zhuolide D-302 UV Glue - Invisible Adhesive for Transparent Glass, Metal, Coffee Tables, and Crystal Glass, 250g Large Capacity

Zhuolide D-302 UV Glue - Invisible Adhesive for Transparent Glass, Metal, Coffee Tables, and Crystal Glass, 250g Large Capacity

$130.00

Hell Training Rock Guitar by Shinichi Kobayashi: Electric Guitar Tutorial for Speed Playing

Hell Training Rock Guitar by Shinichi Kobayashi: Electric Guitar Tutorial for Speed Playing

$106.00

[Buy One Get One Free] Natural Agarwood, Sandalwood, and Cypress Incense Powder Set with Electric Burner

[Buy One Get One Free] Natural Agarwood, Sandalwood, and Cypress Incense Powder Set with Electric Burner

$8.42

Quilt Storage Bag – Large-Capacity Waterproof & Moisture-Proof Moving Pack for Clothes, Luggage, and Comforters

Quilt Storage Bag – Large-Capacity Waterproof & Moisture-Proof Moving Pack for Clothes, Luggage, and Comforters

$10.10

Ins-Style Cute Quilted Cotton Camera Storage Bag for CCD and Instant Cameras, Soft Drop-Proof Dust-Proof Small Pouch

Ins-Style Cute Quilted Cotton Camera Storage Bag for CCD and Instant Cameras, Soft Drop-Proof Dust-Proof Small Pouch

$8.50

Gongma Car Tire Stone Removal Tool Set, Tire Cleaning Hook, Multi-Function Stone Picker and Extractor

Gongma Car Tire Stone Removal Tool Set, Tire Cleaning Hook, Multi-Function Stone Picker and Extractor

$40.00

Feileniao 'Competing Beauties' Traditional Chinese Painting Gift Set - Gongbi Line Drawing DIY Kit for Beginners & New Year Gifts

Feileniao 'Competing Beauties' Traditional Chinese Painting Gift Set - Gongbi Line Drawing DIY Kit for Beginners & New Year Gifts

$41.60

9A Natural Ice-Grade Aquamarine Loose Beads - Handmade DIY Bracelets and Necklaces for Women, Devil Blue Crystal Single Bead

9A Natural Ice-Grade Aquamarine Loose Beads - Handmade DIY Bracelets and Necklaces for Women, Devil Blue Crystal Single Bead

$23.10

High-Precision Digital Tire Pressure Gauge with Large Display for Car Inflation

High-Precision Digital Tire Pressure Gauge with Large Display for Car Inflation

$49.50

Premium Factory Price Low-Temp 3D Printing Pen (2-Pack) - Compatible with PCL Filament

Premium Factory Price Low-Temp 3D Printing Pen (2-Pack) - Compatible with PCL Filament

$67.91

Music Theory Book Jazz Theory Introduction Volume 1 Jazz Teaching Theoretical Knowledge Basic Textbook Tutorial HD Electronic Version

Music Theory Book Jazz Theory Introduction Volume 1 Jazz Teaching Theoretical Knowledge Basic Textbook Tutorial HD Electronic Version

$5.00

Extra-Large Transparent Plastic Storage Box with Lid, Home Organizer for Clothes and Household Items

Extra-Large Transparent Plastic Storage Box with Lid, Home Organizer for Clothes and Household Items

$4.80

Baijiali Artistic Eyebrow Hair Transplant: Bilateral Filling for Sparse Areas, Dense and Natural-Looking Results

Baijiali Artistic Eyebrow Hair Transplant: Bilateral Filling for Sparse Areas, Dense and Natural-Looking Results

$7,800.00

Plastic U-Shaped Trough Mold for Yam Cultivation, Directional Shallow Growth Slots (100 Pieces, Free Shipping)

Plastic U-Shaped Trough Mold for Yam Cultivation, Directional Shallow Growth Slots (100 Pieces, Free Shipping)

$31.40

Maikeku Commercial Slow Juicer, Large Pulp-Separating Juice Extractor with High Power, Wide Mouth, Fully Automatic for Street Vending

Maikeku Commercial Slow Juicer, Large Pulp-Separating Juice Extractor with High Power, Wide Mouth, Fully Automatic for Street Vending

$7,456.32

Continental CSC5 Tire 245/50R18 104V MO-V for Mercedes-Benz Viano, Vito, V260

Continental CSC5 Tire 245/50R18 104V MO-V for Mercedes-Benz Viano, Vito, V260

$882.00

English Vocabulary Flashcards for Classroom Teaching - Categories Include Weather, Days, Months, Clothing, Home, Seasons, Fruits, Food, and Professions

English Vocabulary Flashcards for Classroom Teaching - Categories Include Weather, Days, Months, Clothing, Home, Seasons, Fruits, Food, and Professions

$8.42

Cabinet Storage Box, Foldable Rattan-Style Basket for Countertop Snacks, Clothes, and Toys

Cabinet Storage Box, Foldable Rattan-Style Basket for Countertop Snacks, Clothes, and Toys

$19.90

Custom PVC Sign Letters, Advertising Signs, Branding Wall Characters, Snowflake Board, Acrylic Crystal Letters for Background Walls

Custom PVC Sign Letters, Advertising Signs, Branding Wall Characters, Snowflake Board, Acrylic Crystal Letters for Background Walls

$5.00

Specialized Vegetable Growing Box - Foam Balcony Planter, Rectangular Plastic Pot for Home Gardening

Specialized Vegetable Growing Box - Foam Balcony Planter, Rectangular Plastic Pot for Home Gardening

$41.70

Fully Protected Smart Battery Tester - Performance Detector for Electric Vehicle and Car Batteries

Fully Protected Smart Battery Tester - Performance Detector for Electric Vehicle and Car Batteries

$286.00

Custom Engineering Drainage Pipes Large-Diameter Metal Steel Corrugated Pipes Integrated Assembly Corrugated Pipe Culverts Bridge Culverts

Custom Engineering Drainage Pipes Large-Diameter Metal Steel Corrugated Pipes Integrated Assembly Corrugated Pipe Culverts Bridge Culverts

$61.11

Water Curtain Paint Booth - 3-Meter Spray Station with Water Circulation for Paint Mist Purification, Eco-Friendly Dust Removal, 1-Meter Small Water Curtain Cabinet

Water Curtain Paint Booth - 3-Meter Spray Station with Water Circulation for Paint Mist Purification, Eco-Friendly Dust Removal, 1-Meter Small Water Curtain Cabinet

$1,980.00

Portable Cleaning and Storage Box for Elderly Dentures, Compact Case for Full-Set False Teeth Soaking and Storage

Portable Cleaning and Storage Box for Elderly Dentures, Compact Case for Full-Set False Teeth Soaking and Storage

$32.22

RC Model A07 PNP FPV Analog/Digital Racing Drone 7-Inch Aerial Photography Quadcopter Frame

RC Model A07 PNP FPV Analog/Digital Racing Drone 7-Inch Aerial Photography Quadcopter Frame

$1,643.00

ACCSOON SeeMo Monitor Converter for iPhone and iPad, Real-Time Monitoring and Live Streaming

ACCSOON SeeMo Monitor Converter for iPhone and iPad, Real-Time Monitoring and Live Streaming

$1,059.00

Solenoid Valve Initial Inspection Test Bench / Solenoid Valve Leakage Test Bench / Solenoid Valve Airtightness Test Bench

Solenoid Valve Initial Inspection Test Bench / Solenoid Valve Leakage Test Bench / Solenoid Valve Airtightness Test Bench

$7,482.00

Factory Direct Hardware Screw and Parts Automatic Weighing and Packaging Machine, Vertical Weighing and Packing Equipment

Factory Direct Hardware Screw and Parts Automatic Weighing and Packaging Machine, Vertical Weighing and Packing Equipment

$36,860.00

Commercial Heated Beverage Cabinet, Small Countertop Display Warmer with Constant Temperature for Supermarkets

Commercial Heated Beverage Cabinet, Small Countertop Display Warmer with Constant Temperature for Supermarkets

$1,099.00