Arduino air quality, CCS811, BME280, Dust sensor

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//This code belongs to the following tutorial video: https://youtu.be/6w7Js9SOPwM

//Info: GP2Y1010AU0F Dust sensor
//The dust sensor reaches the maximum output pulse 0.28 ms after the LED was turned on
//This sensor is based on voltage measurement
//CCS811 is a thermometer-VOC meter and uses a premade library -I2C
//BME280 is a thermometer, humidity and pressure sensor - I2C
//OLED: any OLED display can be used, this particular tutorial uses the 128x32 type - I2C

//OLED Libraries
#include "SSD1306Ascii.h"
#include "SSD1306AsciiAvrI2c.h"
#define I2C_ADDRESS 0x3C //Address
#define RST_PIN -1 //For OLED with no reset pin
SSD1306AsciiAvrI2c display;

#include <Wire.h>

//VOC sensor
#include "Adafruit_CCS811.h" //We load the library for the gas sensor
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>
Adafruit_CCS811 ccs;

//BME280
Adafruit_BME280 bme; // I2C
//Use these #define lines if you want to use it with SPI
//#define BME_SCK 13
//#define BME_MISO 12
//#define BME_MOSI 11
//#define BME_CS 10
#define SEALEVELPRESSURE_HPA (1013.25)

//-------------------------------------------
//variables
float co2Amount; //Amount (ug/m^3) of CO2
float CCSTemp; //temperature measured by the CCS811

//Dust sensor
int dustmeasurePin = A3; //The output of the dust sensor is connected to A3 (AD converter pin)
int dustLEDPin = 2; //The IR pin inside the dust sensor is connected to D2 (digital output pin)
float outBits = 0; //AD-converter raw output
float dustDensity = 0; //dust density, based on the formula

//BME280  - Temperature, humidity and pressure sensor.
float BME280Temp;
float BME280Humidity;
float BME280Pressure;
float BME280Altitude;

unsigned long delayTime; //delaytime for BME280 library

//String for storing the formatted output data (serial port)
String outputData;

void setup()
{
    Serial.begin(9600); //Start serial

    Serial.println("*Dust and VOC sensor"); //Print message. I use '*' to tell the receiver software that this is not a measurement data

  //CCS
    if(!ccs.begin()) //if we are not able to start the VOC sensor, print the following message
    {
        Serial.println("* Failed to start sensor! Please check your wiring.");
        while(1); //And hold the code here
    }

    while(!ccs.available());
  //endofCCS

    float temp = ccs.calculateTemperature(); //calculate the temperature
    ccs.setTempOffset(temp - 25.0); //set the offset using the
  //BME280
   unsigned status;
   status = bme.begin(0x76);
   if (!status) {
        Serial.println("*Could not find a valid BME280 sensor, check wiring, address, sensor ID!");
        Serial.print("*SensorID was: 0x"); Serial.println(bme.sensorID(),16);
        Serial.print("*        ID of 0xFF probably means a bad address, a BMP 180 or BMP 085\n");
        Serial.print("*   ID of 0x56-0x58 represents a BMP 280,\n");
        Serial.print("*        ID of 0x60 represents a BME 280.\n");
        Serial.print("*        ID of 0x61 represents a BME 680.\n");
        while (1) delay(10);
    }
    delayTime = 1000;
   //endofBME280

  //OLED part
  #if RST_PIN >= 0
  display.begin(&Adafruit128x32, I2C_ADDRESS, RST_PIN);
  #else // RST_PIN >= 0
  display.begin(&Adafruit128x32, I2C_ADDRESS);
  #endif // RST_PIN >= 0
  //Call oled.setI2cClock(frequency) to change from the default frequency.

  display.setFont(System5x7);
  display.set1X();
  display.clear();
  //--endofOLED----

  pinMode(dustLEDPin,OUTPUT); //the pin for the dust sensor's LED is set as an output
}

void loop()
{
  //we do this part outside of the serial as well, since we need to measure anyway if we want to see the info on the OLED
       measureDust();
       delay(500);
       measureVOCs();
       delay(500);
       MeasureBME280();
       delay(500);
       //Printing the data on the OLED
       refreshOLED();
       delay(1000);
  //

  //We only enter this part, if we sent a character "S" to the serial
  //The printing can be stopped by sending an "N"
    if (Serial.available() > 0) //if there's something on the serial
    {
    char commandCharacter = Serial.read(); //we use characters (letters) for controlling the switch-case

        switch (commandCharacter)
        {
          case 'S': //S: start

          while(Serial.read() != 'N') //while we don't send N through the serial, the following functions are looping:
          {
       measureDust();
       delay(500);
       measureVOCs();
       delay(500);
       MeasureBME280();
       delay(500);
       //Printing the data on the OLED
       refreshOLED();
       delay(1000);
             printFormattedData();     //prints the pre-formatted line on the serial port

          }
          break;

          default:
              //
          break;
          }
  }
}

void measureDust()
{
  digitalWrite(dustLEDPin,LOW); //turn ON the LED

  delayMicroseconds(280); // wait 0.28 ms = 280 us

  outBits = analogRead(dustmeasurePin); //measure the peak of the output pulse

  digitalWrite(dustLEDPin,HIGH); //turn OFF the LED

  /*
  If you want to get the converted data on the Arduino terminal,
  //uncomment this part and replace the outbits to dustDensity in printFormattedData()

  dustDensity = 1000* ( 0.17 * ((5.0 / 1024) * outBits) - 0.1); //dust density in ug/m^3
  */

}

void measureVOCs()
{
    if(ccs.available()) //If we can communicate with the VOC sensor
    {
        if(!ccs.readData()) //if we are not reading (i.e. the devide is available)
        {
            co2Amount = ccs.geteCO2(); //read CO2
            ccs.getTVOC(); //read temperature
            CCSTemp = ccs.calculateTemperature(); //calculate temperature
        }
        else
        {
            Serial.println("ERROR!"); //Print error message
            while(1); //wait here
        }
    }
}

void printFormattedData() //Formatting the output so the receiver software can process it
{

  outputData = (String)CCSTemp +  '\t' + (String)BME280Temp + '\t' + (String)bme.readHumidity() + '\t' + (String)BME280Pressure + '\t'
  + (String)outBits + '\t' + (String)co2Amount; //for the output
  Serial.println(outputData); //print the formatted line

  //Format on serial output: Temp1 (CCS) /tab/ Temp2 (BME) /tab/ Humidity /tab/ Pressure /tab/ Dust /tab/ CO2 /newline/

  //outBits can be replaced to dustDensity to print the converted data instead of the raw data.
  //dustDensity = 1000* ( 0.17 * ((5.0 / 1024) * outBits) - 0.1); //dust density in ug/m^3
}

void MeasureBME280()
{
//Reading all the available values from the BME280 chip
BME280Temp = bme.readTemperature();
BME280Humidity = bme.readHumidity();
BME280Pressure = bme.readPressure() / 100.0F;
BME280Altitude = bme.readAltitude(SEALEVELPRESSURE_HPA);
}

void refreshOLED()
{
  //128x32 OLED
  //1st line of the OLED
  display.clear();
  display.setCursor(0, 0);
  display.print("T: ");
  display.print(BME280Temp);
  display.print("C  H: ");
  display.print(BME280Humidity);
  display.println("%");

  //2nd line
  display.setCursor(0, 1);
  display.print("P: ");
  display.print(BME280Pressure);
  display.print(" A: ");
  display.print(BME280Altitude);
  display.println("m");

  //3rd line
  display.setCursor(0, 2);
  display.print("CO2: ");
  display.print(co2Amount);
  display.print(" ppm");

  //4th line
  display.setCursor(0, 3);
  display.print("D: ");
  display.print(1000* ( 0.17 * ((5.0 / 1024) * outBits) - 0.1));
  display.println(" ug/m3");

}