MiCS-4514 Nitrogen Dioxide Gas Sensor [Arduino Sensors for Everyone]

This chapter explains how to use the MiCS-4514 sensor. You will learn its features, operating principles, specifications, connection pin arrangement, output values, and connect Arduino and the sensor together to measure the air around you easily using the library.

 

Contents

 

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MiCS-4514 Nitrogen Dioxide Gas Sensor

 

 

 

 

 

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Effects on the human body

Nitrogen monoxide is gradually oxidized in the air to become nitrogen dioxide, which becomes a serious problem when inhaled.
 
Nitrogen dioxide can be divided into acute or chronic damage and has a severe effect on the lungs. Acute damage includes eye and nose irritation, pulmonary bleeding, obstructive bronchitis, and pneumonia 
 
Chronic damage occurs in the mucous membranes of the eyes and nose when exposed to high concentrations of 10-40 pppm, and lung fibrosis and pulmonary edema occur when inhaled for a long time. Nitrogen dioxide introduced into the human body through breathing reaches deep into the alveoli, lowering the oxygen-carrying capacity of hemoglobin, and can cause pulmonary edema inflammation with dyspnea within a few hours.
  

 

 

 

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MiCS-4514 Sensor?

MiCS-4514 is a Micro Electro Mechanical Systems (MEMS) sensor that can measure nitrogen dioxide (NO2) and is manufactured by SGX Sensortech.  

MiCS-4514 is a Dual Sensor in One SMD Package product that detects NO2 and CO. It has a short lead time and is suitable for air quality monitoring, gas leak detection, and contamination detection.

 

0278_Datasheet-MiCS-4514-rev-16.pdf

0.37MB

 

 

 

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[MICS-4514 from the SGX SENSORTECH Homepage]

 

 

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[MiCS-4514 sensor specifications ]
The specifications of the MiCS-4514 sensor are as follows.

 

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[Sensitivity of MiCS-4514 sensor (temperature/humidity) ]
As NO2 increases, the value of RS/R0 increases and the voltage decreases in Rs, thus increasing the ADC counter. In addition, the sensor results may vary depending on temperature, humidity, and air pressure.
 
In the MICS-4515 sensor, the measured value of the sensor may be affected depending on the environment by temperature/humidity.

 

 

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The sensor is affected by humidity.
Ambient humidity affects the sensor's reference resistance, sensitivity and responsiveness. Water is absorbed by the sensitive layer and reacts as an exhaust gas. However, this effect is not powerful and can be ignored in some applications. The pulse mode can be used to distinguish humidity from other target gases. These effects must be characterized and corrected to provide absolute measurements.
For example, 15 ppm ozone at 40% RH corresponds to 20 ppm ozone at 80% RH. By adding a filter such as activated carbon, the effects of interference gases such as VOCs or ozone can be suppressed.

 

 

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[Preheat time for MiCS-4514 sensor] 
In order to accurately measure the sensor, it is necessary to consider the effect of the sensor on the air flow.
The sensor is affected by the measured value of the sensor according to the flow of air. The direct airflow on the sensor surface changes the temperature of the heated bed, thus changing the conductivity of the sensor.
That is why SGX Sensortech recommends placing the sensor behind a Teflon membrane for most applications.
The Teflon membrane reduces the effect of air velocity while allowing the gas to diffuse.

  

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MiCS-4514 sensor [airflow]  
In order to accurately measure nitrogen dioxide concentration with the sensor, it is necessary to consider the effect of airflow on the sensor.
Direct airflow on the sensor surface changes the temperature of the heat bed, thus changing the conductivity of the sensor.
SGX Sensortech recommends placing the sensor behind a Teflon membrane for most applications.
The Teflon membrane reduces the effect of airflow while allowing the gas to diffuse.

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[Calibration] of the MiCS-4514 sensor
In order to accurately measure nitrogen dioxide concentration with the sensor, the sensor also needs to be calibrated properly. So, how often should the sensor be calibrated? It depends on the application and the required precision. Several factors tend to reduce measurement accuracy.
For example, it may include factors such as basic resistance (Ro) and sensitivity (S), temperature, humidity, the presence of interference gases, aging of the sensor, and dispersion of production over time. If the required accuracy cannot be achieved due to one or more of the factors listed above, calibration is required. This is the case for most applications where accurate gas measurement is required.

 

 

 

 

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Purchasing the MiCS-4514 sensor

As follows, the [MiCS-4514] sensor used in the book [Arduino Sensors for Everyone] can be purchased at Ali Express, Amazon.  

 

 

 

 

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Software Coding

Run the example file in Steamedu123_Sensor-master > examples.

/*
   @403 MiCS-4514 Nitrogen dioxide gas sensor
*/

#include <C403_Steam_Air_MICS-4514_NO2.h>   // Internal library header file

SteamMICS4514 mics4514(3, A0, A1);     // Instance, pin number(pre, nox, red)

void setup() {
  Serial.begin(9600);       // Start serial communication at a speed of 9600bps.
  mics4514.begin();         // (1) Initialize the sensor.
}

void loop() {
  mics4514.read();          // (2) Measure the value of the sensor.
  mics4514.display();       // (3) Output the sensor value.
  delay(1000);              // Wait for 1 second.
}

 

 

 

 

 

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MiCS-4514 Arduino sensor operation check

When the hardware connection and software coding are completed, you can check the operation screen as follows.

 

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Development environment: WINDOWS 10
Arduino IDE: 1.8.13
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01 library copy

You can easily check the operation by using the  library.  
The libraries \Steamedu123_Sensor-master folder is copied to the folder below.
* This folder is created automatically after installing Arduino C:\Users\s\Documents\Arduino\libraries

02 *. ino file execution
-Connect Arduino and PC
-Run Arduino IDE
-Menu → Tools → Board: Check Arduino UNO
-Menu → Sketch → Check/Compile

03 Check compilation

Select Sketch>OK/Compile (CTRL+R) to compile.

04 Arduino Uno upload

When the compilation is completed without any problems, select Sketch>Upload (CTRL+U) to upload the compiled file.

05 Operation check

You can check the operation as follows.
 

 

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Wrap-up

You can connect Arduino and [MiCS-4514] sensor and practice the sensor easily with simple coding.

 

In this section, we investigated the effects of nitrogen dioxide on the human body, the reference concentration, the measurement range of simple measuring instruments, and the sensors used in measuring instruments. We learned how to control the MiCS-4514 sensor, and with Arduino, we measured nitrogen dioxide concentration.
 
According to the forecast’s 4th level, sensitive people do not need to be particularly restricted in their behavior during outdoor activities, but they should be cautious according to their physical condition.
  
In the forecast level of Bad, it is necessary to limit prolonged and unnecessary outdoor activities, and to use the inhaler more often, especially when a person with asthma is outdoors. People who have symptoms of sore eyes, or who are uncomfortable with coughing or sore throat, should avoid outdoor activities
 
In the forecast level of Very Bad, stay indoors as much as possible, and people with symptoms such as sore throat and cough should avoid outdoor activities.
  
In addition, when the atmospheric concentration of nitrogen dioxide is high, it can be introduced into the room. Nitrogen dioxide can be produced when cooking food. Therefore, according to the indoor air quality of the enforcement regulations of the Indoor Air Quality Management Act (Article 4), multi-use facilities has a recommended nitrogen dioxide standard concentration of 0.05 ppm or less. In high concentration conditions, open windows should be closed, and nitrogen dioxide should not enter the interior from the outside. 

The MiCS-4514 nitrogen dioxide sensor can be used not only outdoors but also indoors to measure nitrogen dioxide. When the concentration of nitrogen dioxide in the atmosphere is high, it may be introduced indoors, or nitrogen dioxide may be generated when cooking. Nitrogen dioxide cannot be removed with an air purifier, so if the concentration of nitrogen dioxide is high indoors, ventilation should be performed frequently.
 

 

 

 

 

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References

References for [MiCS-4514 Nitrogen dioxide (NO2) Arduino sensor] used in the book [Arduino for Everyone: Environmental Sensors] are as follows. 

 

[23] Air Korea real-time atmosphere information, 

[24] Air Korea Air Quality Standards (Overseas), 

[25] SGX Sensortech, MiCS-4514 Datasheet, 

[26] SEPC SENSORS DGS-NO2 Datasheet, 

[27] Winsen ZE03 Datasheet, 

[28] AliExpress MiCS-4514, 

[29] SEPC SENSORS DGS-NO2, https://bit.ly/3oUOzdj

[30] AliExpress Winsen ZE03-NO2, https://aliexpi.com/XSHx

[31] 0278_Datasheet-MiCS-4514-rev-16, "MiCS-4514 with measurement circuit(top view)", p3

[32] 0278_Datasheet-MiCS-4514-rev-16, "Parameter RED sensor/OX sensor", p3

[33] CJMCU-4541原理图.pdf

[34] 0278_Datasheet-MiCS-4514-rev-16, "OX sensor, continuous power ON", p1

 

 

 

 

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Purchasing a book

[Arduino Sensors for Everyone] The book is available for purchase on Google Book and Apple Books.

In this book, you will learn how to use the PMS7003, GP2Y1010AU0F, PPD42NS, SDS011 Fine Dust Sensor, DHT22 temperature/humidity sensor, MH-Z19B carbon dioxide sensor, ZE08-CH2O formaldehyde sensor, CCS811 total volatile organic compound (TVOC) sensor , GDK101 radiation (gamma ray) sensor, MQ-131 ozone (O3) sensor, MQ-7 carbon monoxide sensor, MICS-4514 nitrogen dioxide sensor, MICS-6814 ammonia sensor, DGS-SO2 sulfur dioxide (SO2) sensor, BME280 atmospheric pressure sensor, GUVA-S12SD ultraviolet (UV) sensor, MD0550 airflow sensor, and QS-FS01 wind speed sensor.

 

[Google play book]

Arduino Sensors for Everyone, 저자: Ronnie Kim - Google Play 도서