Adjustable Air Quality Monitoring & Analysis Platform with Plug-UnPlug System

1#include <AirQuality.h>
2#include <Correction.h>
3#include <GasSensor.h>
4#include <SensorDefinitions.h>
5
6#include <LiquidCrystal_I2C.h>
7
8#define ADC_BIT_RESU (12) // for ESP32
9#define pin          (35) // D35 (ADC1)
10#define pot          (34) // D35 (ADC1)
11
12int Air, ppm;
13float sensorVal, temp, rh, correction;
14String selectedModel, mode;
15
16GasSensor sensor(ADC_BIT_RESU, pin);
17SensorModel* sensorModel = nullptr;
18
19String mqList1[] = { "MQ135", "MQ2", "MQ3", "MQ4", "MQ5", "MQ6", "MQ7", "MQ8", "MQ9", "MQ136", "MQ137", "MQ138", "MQ214" };
20String mqList2[] = { "MQ303A", "MQ303B", "MQ307A", "MQ309A" };
21String mqList3[] = { "MQ131", "MQ131_LOW" };
22
23int lcdColumns = 16;
24int lcdRows = 2;
25
26LiquidCrystal_I2C lcd(0x27, lcdColumns, lcdRows); 
27
28void setup() {
29    Serial.begin(115200); // for ESP32
30    sensor.begin();
31    lcd.init();
32    lcd.backlight();
33    // WARNING: Please run the code after connecting the appropriate resistance specified 
34    // in the Required_MQ_LoadResistor.ino file to the sensor mode you selected, 
35    // otherwise the results will not reflect the reality.
36}
37
38void loop() {
39    int val = map(analogRead(pot), 0, (1 << ADC_BIT_RESU) - 1, 1, 19);
40
41    if (val >= 1 && val <= 13) selectedModel = mqList1[val - 1];
42    else if (val >= 14 && val <= 17) selectedModel = mqList2[val - 14];
43    else if (val >= 18 && val <= 19) selectedModel = mqList3[val - 18];
44
45    sensorModel = getSensorModel(selectedModel);
46    if (!sensorModel) {
47        Serial.println("Sensor model not found.");
48        while (true);
49    }
50    Serial.print("Selected sensor: ");
51    Serial.println(sensorModel->model);
52    mode = sensorModel->model;
53   
54    temp = 20.0; // DHT22 is recommended °C (Celsius)
55    rh = 33.0;   // DHT22 is recommended %  (Relative Humidity)
56
57    /* NOTE: The temperature and humidity of the environment do not have a direct effect on the ppm value of the environment.
58    On the other hand, the temperature and humidity of the environment will cause the sensor to detect ppm more or less than normal. 
59    The amount of deviation of the erroneous measurement caused by environmental conditions is modeled by the data graphs of each sensor.
60    In this case, this error margin calculated with the Correction Coefficient, known as Correction.h, is necessary to correct the incorrect ppm value.
61    
62    At 20°C, 33% RH, correction = 1.0 is the environmental condition where the sensor accuracy rate is highest.
63    If the correction coefficient is greater than 1.0, the sensor will measure values ​​lower​​ than the true value, and if it is less than 1.0, 
64    it will measure values higher than the true value. Temperature and humidity are inversely proportional to the correction coefficient. */
65     
66    sensorVal = sensor.read();
67    correction = sensorModel->useCorrection ? calculateCorrection(temp, rh, selectedModel) : 1.0;
68
69    Air = sensorVal > 0 && mode != "MQ307A" ? airConcentration(mode, sensorVal) * correction : 0;
70   
71    if (mode == "MQ3") Air *= 50.0; // mg/L --> ppm
72    if (mode == "MQ131_LOW") Air *= 0.02; // ppb --> ppm
73   
74    lcd.setCursor(0, 0);
75    lcd.print("Air: " + String(Air));
76
77    lcd.setCursor(16 - mode.length(), 0);
78    lcd.print(mode);
79
80    lcd.setCursor(0, 1); // Correction --> CR
81    lcd.print("CR: x" + String(correction, 4));
82
83    lcd.setCursor(13, 1);
84    lcd.print("ppm");
85
86    delay(3000);
87    lcd.clear();
88
89    for (byte i = 0; i < sensorModel->gasCount; i++) {
90        const GasModel& gasType = sensorModel->gasList[i];
91
92        if (isMQSensor(mode, mqList1, sizeof(mqList1) / sizeof(mqList1[0]))) {
93          float RsRocalValue = sensor.calculateCalValue1(gasType.a, gasType.b, sensorModel->calibrateAir, gasType.minPpm, gasType.maxPpm);
94          ppm = sensor.calculateRsRoPPM(sensorVal, correction, gasType.a, gasType.b, RsRocalValue, sensorModel->air, sensorModel->rlcal, gasType.maxPpm);
95          if (mode == "MQ3") ppm *= 50.0;
96        } 
97
98        else if (isMQSensor(mode, mqList2, sizeof(mqList2) / sizeof(mqList2[0]))) {
99          float RsRscalValue = sensor.calculateCalValue2(gasType.a, gasType.b, sensorModel->calibrateAir, gasType.minPpm, gasType.maxPpm);
100          if (mode == "MQ307A" && i == 1) RsRscalValue = 0.999619;
101          if (mode == "MQ309A" && i >= 2) RsRscalValue = 0.83393;
102          ppm = sensor.calculateRsRsPPM(sensorVal, gasType.a, gasType.b, RsRscalValue, sensorModel->rlcal, gasType.maxPpm);
103        }
104
105        else if (isMQSensor(mode, mqList3, sizeof(mqList3) / sizeof(mqList3[0]))) {
106          float RoRscalValue = sensor.calculateCalValue1(gasType.a, gasType.b, sensorModel->calibrateAir, gasType.minPpm, gasType.maxPpm);
107          ppm = sensor.calculateRoRsPPM(sensorVal, correction, gasType.a, gasType.b, RoRscalValue, sensorModel->air, sensorModel->rlcal, gasType.maxPpm);
108          if (mode == "MQ131_LOW") ppm *= 0.02;
109        }
110
111        lcd.setCursor(0, 0);
112        lcd.print("Air: " + String(Air));
113	
114        lcd.setCursor(16 - mode.length(), 0);
115        lcd.print(mode);
116
117        lcd.setCursor(0, 1);
118        lcd.print(String(gasType.gasName) + ": " + String(ppm));
119
120        lcd.setCursor(13, 1);
121        lcd.print("ppm");
122
123        delay(1500);
124        lcd.clear();
125    }
126
127    Serial.println("----------");
128    delay(5000);
129}