Gas Sensor(MQ-135):

Here are some key points about the MQ-135 gas sensor:

Working Principle:

The MQ-135 operates on the principle of metal oxide semiconductor (MOS).
The sensor's resistance changes when it comes into contact with different gases. This change in resistance is used to detect the concentration of the targeted gases.

Sensitivity:The sensitivity of the MQ-135 can vary for different gases. It is generally more sensitive to gases like ammonia and less sensitive to some others.The sensitivity is affected by factors such as temperature and humidity.

Calibration:Calibration is often required to obtain accurate and reliable results.
The sensor needs to be preheated for a certain period before use to stabilize its readings.

Interfacing:The MQ-135 can be interfaced with microcontrollers like Arduino, Raspberry Pi, or other embedded systems.
Analog voltage output or digital signals can be used to interpret the gas concentration levels.

Applications:Common applications include air quality monitoring, gas leakage detection, industrial safety, and environmental monitoring.

Limitations:The sensor may have some cross-sensitivity to different gases, so it's essential to understand its limitations.
It requires periodic calibration to maintain accuracy.

Cautions:The sensor should be used within its specified operating conditions, and exposure to high concentrations of certain gases should be avoided.