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MQ-135 Air Quality Gas Sensor Module

SKU: JL92ND9M6D
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4.9 (80 reviews)
The MQ-135 Air Quality Gas Sensor Module is a semiconductor-based gas detection module designed to monitor indoor air quality by detecting a wide range of harmful gases, including ammonia (NH₃), nitrogen oxides (NOx), benzene, alcohol, smoke, carbon dioxide (CO₂), sulfide, and other volatile organic compounds (VOCs). Built around the MQ-135 gas sensor and an onboard LM393 voltage comparator, the module...
Rs. 139.00
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The MQ-135 Air Quality Gas Sensor Module is a semiconductor-based gas detection module designed to monitor indoor air quality by detecting a wide range of harmful gases, including ammonia (NH₃), nitrogen oxides (NOx), benzene, alcohol, smoke, carbon dioxide (CO₂), sulfide, and other volatile organic compounds (VOCs). Built around the MQ-135 gas sensor and an onboard LM393 voltage comparator, the module provides both analog (AO) and digital (DO) outputs for easy interfacing with microcontrollers.

Operating at 5V DC, the module features an adjustable sensitivity potentiometer that allows users to set the digital detection threshold according to their application. Its fast response time, long operational life, and stable performance make it suitable for air quality monitoring, smart home systems, industrial safety equipment, environmental monitoring, and educational electronics projects. Compatible with Arduino, ESP32, STM32, Raspberry Pi (with ADC for analog input if required), PIC, AVR, and other development platforms, the MQ-135 is one of the most widely used air quality sensors for embedded systems.

Key Features

  • Based on the MQ-135 semiconductor gas sensor
  • Detects multiple harmful gases and pollutants
  • Sensitive to NH₃, NOx, CO₂, benzene, alcohol, smoke, and VOCs
  • Dual analog and digital outputs
  • Built-in LM393 voltage comparator
  • Adjustable sensitivity via onboard potentiometer
  • Fast response and recovery time
  • High sensitivity with stable performance
  • Power and output indicator LEDs
  • Long operational life
  • Low-cost and easy to integrate
  • Operates from 5V DC
  • Compatible with Arduino, ESP32, STM32, Raspberry Pi, AVR, and PIC
  • Ideal for air quality monitoring and environmental sensing

Shipping & Returns

Orders placed before 3 PM IST will be shipped on the same day (excluding Sundays and Public holidays) through our shipping partners. In rare cases, the pickup may get delayed during Public holidays / Bandh / Environmental disturbances.

Specifications

Specifications:

Module Type: Air Quality Gas Sensor Module
Sensor Model: MQ-135
Sensor Technology: Semiconductor (SnO₂)
Comparator IC: LM393
Operating Voltage: 5V DC
Operating Current: Approximately 150mA
Heater Voltage: 5V ±0.1V
Heater Resistance: Approximately 33Ω ±5%
Heating Power Consumption: Less than 800mW
Target Gases: Ammonia (NH₃), Nitrogen Oxides (NOx), Benzene, Alcohol, Smoke, CO₂, Sulfide, VOCs
Detection Range: Approximately 10–1000ppm (Ammonia, Benzene, Hydrogen, Smoke)
Output Type: Analog (AO) and Digital (DO)
Digital Output: TTL Logic Level
Analog Output Voltage: 0V–5V
Sensitivity Adjustment: Onboard Potentiometer
Response Time: Fast Response
Preheat Time: Initial Burn-in Recommended Over 24 Hours; Short Warm-Up Required Before Normal Operation
Operating Temperature: -10°C to +45°C
Operating Humidity: Up to 95% RH (Non-Condensing)
Module Dimensions: Approximately 32mm × 22mm × 27mm
Mounting Type: PCB Module with Mounting Holes
Compatibility: Arduino UNO, Nano, Mega, ESP32, STM32, Raspberry Pi (with ADC where required), AVR, PIC, 8051 and other microcontrollers

Additional Resources

MQ-135.PDF

FAQ

1. What is the MQ-135 Air Quality Gas Sensor Module used for?

The MQ-135 is used to monitor indoor air quality by detecting gases such as ammonia, nitrogen oxides, benzene, smoke, alcohol, CO₂, and other harmful airborne pollutants. It is commonly used in environmental monitoring, smart homes, industrial safety systems, and IoT projects.

2. Does the MQ-135 module provide both analog and digital outputs?

Yes. The module provides an analog output (AO) for measuring relative gas concentration and a digital output (DO) with an adjustable threshold using the onboard potentiometer.

3. Can the MQ-135 sensor accurately measure CO₂ concentration?

The MQ-135 is primarily an air quality sensor that responds to multiple gases. While it is sensitive to CO₂, it does not provide laboratory-grade CO₂ measurements. For accurate CO₂ monitoring, a dedicated NDIR CO₂ sensor is recommended.

4. Is the MQ-135 compatible with Arduino and ESP32?

Yes. The module is compatible with Arduino, ESP32, STM32, AVR, PIC, and Raspberry Pi. For analog measurements on Raspberry Pi, an external ADC is required.

5. Why does the MQ-135 require a preheating period?

The MQ-135 contains an internal heater that stabilizes the sensing element. A short warm-up period is required before normal operation, while an initial burn-in period of more than 24 hours is recommended for improved accuracy and stability.