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Sensors
MQ-135: Volatile Gasses Air Quality
Introduction
The MQ-135 sensor detects volatile gases in the atmosphere that can rise to dangerous levels. Volatility refers to how easily a substance will vaporize into a gas. Unfortunately, many volatile gases are toxic and harmful to life, and can be quite flammable as well; fortunately, we have sensors that can detect these substances and alert us to their presence! MQ-135s measure ammonia (NH3), sulfide, aromatic (benzene-ring based), nitrogen oxide, and alcohol vapors. This sensor can be used for a variety of applications where gas contaminants are a concern. We’ve even heard of one person who used it as a monitor for when to change their family cat’s litterbox!
Sensor Working Principle
MQ-135 sensors use a conductivity meter with a tin oxide (SnO2) material that has low conductivity in pure air. When volatile gas contaminant levels increase in the sensor ambient environment, the conductivity increases according to concentration of volatiles in the air.
Sources
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