Waveshare MQ-135 Air Quality Gas Sensor Module - Analog/Digital Output
Waveshare MQ-135 Air Quality Gas Sensor Module - Analog/Digital Output - Image 2
Waveshare MQ-135 Air Quality Gas Sensor Module - Analog/Digital Output - Image 3
SKU: SENS-0918
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Waveshare MQ-135 Air Quality Gas Sensor Module - Analog/Digital Output

₹459.00 (Inclusive of all taxes)
Out of Stock

The Waveshare MQ-135 is a metal oxide semiconductor (MOS) gas sensor module designed for air quality monitoring, compatible with 5V and 3.3V microcontroller systems like Arduino and Raspberry Pi. It provides both analog and digital outputs for detecting a range of volatile organic compounds (VOCs) including benzene, alcohol, and smoke.

Features

  • Tin dioxide (SnO2) semiconductor sensing element for VOC detection.
  • Dual output: analog voltage signal (AOUT) and digital trigger (DOUT).
  • On-board potentiometer for adjustable digital output sensitivity.
  • Wide operating voltage range from 2.5V to 5.0V DC.
  • Compact PCB module with mounting holes for easy integration.

Out of stock

Description

The MQ-135 sensor module utilizes a tin dioxide (SnO2) semiconductor layer whose conductivity increases in the presence of reducing gases. This change in conductivity is converted into a corresponding analog output voltage, which can be read by an ADC pin on a microcontroller. The digital output provides a high/low signal when gas concentration exceeds a user-adjustable threshold, set via the on-board potentiometer.

Designed for indoor air quality assessment, the module is suitable for integration into environmental monitoring systems, smart home devices, and industrial safety applications. Its simple interface and robust construction make it a practical choice for prototyping and educational projects focused on gas sensing.

Key Features

  • MOS (Metal Oxide Semiconductor) sensing technology for reliable VOC detection.
  • Dual-signal output: analog for concentration measurement and digital for threshold alarms.
  • On-board signal conditioning circuitry and power indicator LED.
  • Manually adjustable sensitivity via a precision potentiometer.
  • Optimized performance-to-cost ratio for educational and prototyping applications.
  • Stable baseline performance in clean air conditions.

Applications

  • Indoor air quality monitors and smart ventilation controllers.
  • Prototype and educational kits for environmental sensing.
  • Safety alarms for benzene or alcohol vapor detection in workshops.
  • Air purifier and HVAC system integration for pollutant triggering.

Technical Specifications

Item TypeGas Sensor Module
Operating Voltage2.5V to 5.0V DC
Detecting Range (NH3)10 ppm to 300 ppm
Detecting Range (Benzene)10 ppm to 1000 ppm
Detecting Range (Alcohol)10 ppm to 300 ppm
Output SignalsAnalog Output (AOUT), Digital Output (DOUT)
Relative Humidity<95% RH
Dimensions (L x W)40.0 mm x 20.0 mm
WeightApprox. 7 g

Frequently Asked Questions

What is the operating voltage range for the MQ-135 module?

The module operates from 2.5V to 5.0V DC, making it compatible with both 5V systems like standard Arduino boards and 3.3V systems like Raspberry Pi or ESP32 with appropriate level shifting or direct connection within its range.

How do the analog and digital outputs work?

The analog output (AOUT) provides a voltage signal proportional to the detected gas concentration, which should be read by an ADC pin on your microcontroller. The digital output (DOUT) switches from high to low (or vice-versa) when the gas concentration exceeds a threshold set by the on-board potentiometer.

What gases does the MQ-135 sensor detect?

The MQ-135 is primarily sensitive to benzene, alcohol (ethanol), and smoke (combustion byproducts). It is designed as a general air quality sensor for volatile organic compounds (VOCs) and is not selective to a single specific gas.

Does the sensor require calibration?

For qualitative detection and threshold alarms using the digital output, calibration is not strictly necessary. For accurate quantitative concentration measurement via the analog output, baseline calibration in clean air and periodic recalibration against known gas concentrations are recommended for reliable results.

Package Includes

  • 1 x Waveshare MQ-135 Gas Sensor Module

Additional Information

Weight 0.007 kg
Dimensions 4 × 2 cm

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