MQ-135 Gas Sensor

DETECTION CAPABILITY: Designed to detect a wide range of gases including ammonia (NH₃), nitrogen oxides (NOx), benzene, smoke, alcohol vapors, and carbon dioxide (CO₂), making it suitable for air quality monitoring applications
DETECTION RANGE: Supports gas concentration detection typically from 10 ppm to 1000 ppm, enabling monitoring of low to moderate levels of harmful gases
POWER SPECIFICATIONS: Operates with a 5V DC supply, ensuring compatibility with most microcontrollers and embedded sensing systems
SENSING PRINCIPLE: Utilizes a metal oxide semiconductor (MOS) sensing element based on SnO₂, where sensor conductivity increases as the concentration of target gases rises
INTERFACE DESIGN: Provides analog and digital output signals, allowing direct interfacing with microcontrollers, Arduino boards, and environmental monitoring systems
PIN CONFIGURATION: Features a 4-pin interface (VCC, GND, DO, AO) where AO delivers analog gas concentration output and DO provides threshold-based digital detection
SENSITIVITY CONTROL: Includes an adjustable onboard potentiometer to modify the digital output sensitivity according to application requirements
STATUS INDICATION: Integrated signal indicator LED displays gas detection activity and module operation status
MODULE DIMENSIONS: Compact module structure measuring approximately 3 × 2 × 1 cm, suitable for integration into embedded air quality monitoring devices
APPLICATION SCOPE: Widely used in air quality monitoring systems, indoor pollution detection, industrial gas monitoring, portable environmental sensing devices, and smart home safety systems