MQ-135 Air Quality/Gas Detector Sensor Module for Arduino: The MQ-135 Air Quality Detector Sensor Module is an effective and low-cost solution for monitoring air quality and detecting harmful gases. It works by measuring changes in conductivity: low conductivity indicates clean air, while higher conductivity signifies the presence of combustible or hazardous gases. This sensor is particularly sensitive to Ammonia, Sulphide, Benzene steam, and smoke, making it ideal for applications requiring the detection of harmful gases or smoke in the environment. Key Features: High Sensitivity: Detects Ammonia, Sulphide, Benzene steam, and other harmful gases. Wide Gas Detection: Also responsive to benzene, alcohol, and smoke. Signal Outputs: Analog Output (0~5V): The output voltage increases with the concentration of detected gases. TTL Output: Provides a low-level digital signal for easy interfacing. Adjustable Sensitivity: Tune the sensor sensitivity using the onboard potentiometer. Fast Response and Recovery: Quickly detects and resets to changes in air quality. Signal Indicators: LED indicators show power and signal output status. Specifications: Operating Voltage: 5V DC Output Voltage Range: 0 ~ 5V (analog) Signal Output: Digital low-level TTL and analog output Sensitivity: Adjustable via onboard potentiometer Gas Detection: Ammonia, Sulphide, Benzene steam, alcohol, and smoke Dimensions: Compact and easy to integrate into Arduino or other microcontroller-based systems Applications: Air Quality Monitoring: Ideal for indoor and outdoor air quality systems. Safety Systems: Detect harmful gases in homes, offices, or industrial environments. Consumer Devices: Used in smart air purifiers and gas leak alarms. Environmental Monitoring: Track pollution levels in urban and industrial areas. The MQ-135 Air Quality Detector Sensor Module for Arduino is an essential tool for creating projects that monitor and improve air quality. Its versatility, ease of integration, and reliability make it a popular choice for DIY and professional applications alike.