//Code incorporates the following sources (Author. Source Title. URL):
//Arduino instruction book. "Crystal Ball."
//Druhi_C. "Temperature and Humidity sensor with LCD 1602 I2C display." https://projecthub.arduino.cc/Druhi_C/temperature-and-humidity-sensor-with-lcd-1602-i2c-display-a2861e
//codebender_cc. "How to Use DHT-22 Sensor - Arduino Tutorial." https://www.instructables.com/How-to-use-DHT-22-sensor-Arduino-Tutorial/
//arduino-libraries, “SD/examples/Datalogger/Datalogger.ino at master · arduino-libraries/SD,” GitHub, 2015. https://github.com/arduino-libraries/SD/blob/master/examples/Datalogger/Datalogger.ino (accessed Feb. 26, 2024).

//Libraries
#include <DHT.h>;
#include <LiquidCrystal.h>
#include <SPI.h>
#include <SD.h>

//Constants
#define DHTPIN 3     // Which pin DHT sensor is connected to
#define DHTTYPE DHT22   // DHT 22  (AM2302)
const int chipSelect = 6;  // Which pin SD card is written to

//Initialize
DHT dht(DHTPIN, DHTTYPE); //// Initialize DHT sensor for normal 16mhz Arduino
LiquidCrystal lcd(12,11,10,9,8,7); // generates an instance in the lcd

//Variables
int chk;
float hum;  //Stores humidity value
float tempC; //Stores temperature value in C
float tempF =  (tempC * 9.0 / 5.0) + 32.0;

void setup()
{
  Serial.begin(9600);
	dht.begin();
  lcd.begin(16,2); 
  SD.begin(chipSelect);

///////////////////////////////////////////////
 while (!Serial);

  Serial.print("Initializing SD card...");

  if (!SD.begin(chipSelect)) {
    Serial.println("initialization failed. Things to check:");
    Serial.println("1. Is a card inserted?");
    Serial.println("2. Is your wiring correct?");
    Serial.println("3. Did you change the chipSelect pin to match your shield or module?");
    Serial.println("Note: press reset button on the board and reopen this Serial Monitor after fixing your issue!");
    while (true);
  }

  Serial.println("initialization done.");
//////////////////////////////////////////////
}

void loop()
{
    //Read data and store it to variables hum and tempC for DHT sensor.
    hum = dht.readHumidity();
    tempC= dht.readTemperature();
    //Print temp and humidity values to serial monitor
    Serial.print("Humidity: ");
    Serial.print(hum);
    Serial.print(" %, Temp: ");
    Serial.print(tempC);
    Serial.println(" Celsius");
    delay(1000); //Delay 1 sec.

    //Read humidity and temperaure data and display it on the LCD.
	  lcd.setCursor(0,0);// set the cursor on the first row and column 
	  lcd.print("Hum="); 
	  lcd.print((float)dht.readHumidity());//print the humidity 
	  lcd.print("%"); 
	  lcd.setCursor(0,1);//set the cursor on the second row and first column 
	  lcd.print("T="); 
	  lcd.print((float)dht.readTemperature());//print the temperature in C
	  lcd.print("C|");
    lcd.print((float)dht.readTemperature() * (9.0 / 5.0) + 32.0);//print the temperature in F
	  lcd.print("F"); 
	  delay(1000);  
///////////////////////////////////////
    // Make a string for assembling the data to log to the SD card:
  String dataString = "";

  // read three sensors and append to the string:
  for (int analogPin = 0; analogPin < 3; analogPin++) {
    int sensor = analogRead(analogPin);
    dataString += String(sensor);
    if (analogPin < 2) {
      dataString += ",";
    }
  }

  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  //Use 
  File dataFile2 = SD.open("wokwi.txt", FILE_WRITE); //Use "wokwi.txt" for simulations. Else, use datalog.text for IRL.

  // if the file is available, write to it:
  if (dataFile2) {
    dataFile2.println(dataString);
    dataFile2.close();
    // print to the serial port too:
    Serial.println(dataString);
  }

  // if the file isn't open, pop up an error:
  else {
    Serial.println("error opening datalog.txt");
  }
/////////////////////////////////////////////////
}