//1. This code is tested on Arduino Uno with Arduino IDE 1.0.5 r2 and 1.8.2.
//2. Calibration of the TDS Sensor (input the following):
   //enter -> (enter calibration mode)
   //cal:tds value -> (calibrate with the known tds value(25°C), e.g., cal:1000
   //exit -> (save the parameters and exit calibration mode)


#include <EEPROM.h>
#include <SPI.h>
#include <SD.h>
#include "GravityTDS.h"
#include <DHT11.h>
#include <Wire.h>
#include <RTClib.h>


RTC_DS1307 rtc;


#define TdsSensorPin A1
GravityTDS gravityTds;


#define DHTPIN 2
DHT11 dht11(DHTPIN);


#define SD_CS 10 
File dataFile;
#define Offset 44.57


#define PH_SensorPin A0
#define LED 13
double avgValue;
float phValue;


float temperature = 25, tdsValue = 0;
int humidity = 0;


void setup()
{
Serial.begin(115200);
if (!rtc.begin()) {
   Serial.println("Couldn't find RTC");
   while (1);
 }
//(Only uncomment the below code once to set the date and time for the RTC module)
//rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
gravityTds.setPin(TdsSensorPin);
gravityTds.setAref(5.0);
gravityTds.setAdcRange(1024); 
gravityTds.begin(); 


if (!SD.begin(SD_CS)) {
   Serial.println("SD card initialization failed!");
   while (1);
  }


Serial.println("SD card ready");


dataFile = SD.open("tds.csv", FILE_WRITE);


  if (dataFile)
  {
   dataFile.println("DateTime,Temperature_C,Humidity_%,TDS_ppm,pH");
   dataFile.close();
  }


}


void loop()
{


DateTime now = rtc.now();


int airTemp;


int result = dht11.readTemperatureHumidity(airTemp, humidity);


if (result == 0)
{
   temperature = airTemp;
}
   // Reading successful
else
{
   Serial.println(DHT11::getErrorString(result));
}
//Reading unsuccessful


  // == TDS SENSOR ==
  gravityTds.setTemperature(temperature);
  gravityTds.update();
  tdsValue = gravityTds.getTdsValue();


  // == pH SENSOR ==
  int buf[10];


  for(int i=0;i<10;i++)
  {
      buf[i] = analogRead(PH_SensorPin);
      delay(10);
  }


  for(int i=0;i<9;i++)
  {
      for(int j=i+1;j<10;j++)
      {
          if(buf[i] > buf[j])
          {
              int temp = buf[i];
              buf[i] = buf[j];
              buf[j] = temp;
          }
      }
  }


  avgValue = 0;


  for(int i=2;i<8;i++)
  {
      avgValue += buf[i];
  }


  float voltage = (float)avgValue * 5.0 / 1024.0 / 6.0;
  phValue = -8.13 * voltage + Offset;


  // == SERIAL OUTPUT ==
  Serial.print("RTC: ");
  Serial.print(now.year());
  Serial.print("-");
  Serial.print(now.month());
  Serial.print("-");
  Serial.print(now.day());
  Serial.print(" ");
  Serial.print(now.hour());
  Serial.print(":");
  Serial.print(now.minute());
  Serial.print(":");
  Serial.println(now.second());
  Serial.print("Temp: ");
  Serial.print(temperature);
  Serial.print(" C  ");
  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.print("%  ");
  Serial.print("TDS: ");
  Serial.print(tdsValue,0);
  Serial.print(" ppm");
  Serial.print("    pH: ");
  Serial.println(phValue,2);


  // == SD CARD LOGGING ==
dataFile = SD.open("tds.csv", FILE_WRITE);




if(dataFile)
  {
   dataFile.print(now.year());
   dataFile.print("-");
   if (now.month() < 10) dataFile.print("0");
      dataFile.print(now.month());
      dataFile.print("-");
   if (now.day() < 10) dataFile.print("0");
      dataFile.print(now.day());
      dataFile.print(" ");
   if (now.hour() < 10) dataFile.print("0");
      dataFile.print(now.hour());
      dataFile.print(":");
   if (now.minute() < 10) dataFile.print("0");
      dataFile.print(now.minute());
      dataFile.print(":");
   if (now.second() < 10) dataFile.print("0");
      dataFile.print(now.second());
      dataFile.print(",");
   dataFile.print(temperature);
   dataFile.print(",");
   dataFile.print(humidity);
   dataFile.print(",");
   dataFile.print(tdsValue,0);
   dataFile.print(",");


   dataFile.println(phValue,2);
 
   dataFile.close();
  }
else
  {
   Serial.println("Error opening data.csv");
  }


  delay(1000);
}