/*
 * Datalogger for Condensing Engine Project
 */

#include <SD.h>            // uses SD libray files via Sketch/Include_library manager
#include <SPI.h>           // uses SPI library files via Sketch/Include_library manager

#define PCylIn_PIN A5      // Set the pressure transducer for the cylinder inlet to pin A0
#define PCylOut_PIN A1     // Set the pressure transducer for the cylinder outlet to pin A1
#define PCondOut_PIN A2    // Set the pressure transducer for the condenser outlet to pin A2

#define TCondIn_PIN A10       // Set the thermocouple for the condenser inlet water to pin A10
#define TCondOut_PIN A15        // Set the thermocouple for the condenser outlet water to pin A15

#define AREF 5.0             // set to AREF, typically board voltage like 3.3 or 5.0
#define ADC_RESOLUTION 1024  // set to ADC bit resolution, 10 bits is default which is 1024 values 

const int chipSelect = 4;  // value to set SD card

unsigned long TimeStamp; // set the time stamp value as an unsigned long variable

String dataString = "";  // make a string for assembling the data to log

float reading, voltage, temperature, pressure; // Set value types to floating numbers for these variables
float CylinderInletPressure, CylinderOutletPressure, CondenserOutletPressure, CondenserTempIn, CondenserTempOut; // Set value types to floating numbers for these variables

// Set up equations to be used in data reading
float get_voltage(int raw_adc) {
  return raw_adc * (AREF / ADC_RESOLUTION);  
}

float get_temperature(float voltage) {
  return (voltage - 1.25) / 0.005;
}

float get_pressure(float voltage) {
  return ((2 * voltage) - 1);
} 


void setup() {
  // put your setup code here, to run once:
  
    // Open serial communications and wait for port to open:
  Serial.begin(115200);

  // Set up SD card
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

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

  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    Serial.println("Card failed, or not present");
    // don't do anything more:
    return;
  }
  Serial.println("card initialized.");

// Write header information at start of data log. Open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  // Note, the datafile must already exist on the SD card. Creat a .txt file with desired name and type that into the quotations below to open.
  File dataFile = SD.open("datalog.txt", FILE_WRITE); // 

  // if the file is available, write to it:
  if (dataFile) {
    // write header information to SD card
    dataFile.println("Date and Test Type");  // Type here what you would like to be printed at the top of the file to distinguish it from others
    dataFile.println("TimeStamp(ms), CylinderInletPressure, CylinderOutletPressure, CondenserOutletPressure, CondenserTempIn, CondenserTempOut"); // Print the data headings    
    dataFile.close();
    // print to the serial port too:
    // write header information to serial monitor
    Serial.println("TimeStamp(ms), CylinderInletPressure, CylinderOutletPressure, CondenserOutletPressure, CondenserTempIn, CondenserTempOut");      
  }
  // if the file isn't open, pop up an error:
  else {
    Serial.println("error opening datalog.txt");
}
}


void loop() {
// put your main code here, to run repeatedly:

  // Call for current time stamp to print:
  TimeStamp = millis();

  // read the five sensors and convert values to desire units:
  reading = analogRead(PCylIn_PIN); 
  voltage = get_voltage(reading);  
  CylinderInletPressure = get_pressure(voltage); 
   
  reading = analogRead(PCylOut_PIN); 
  voltage = get_voltage(reading);  
  CylinderOutletPressure = get_pressure(voltage);  
   
  reading = analogRead(PCondOut_PIN); 
  voltage = get_voltage(reading);  
  CondenserOutletPressure = get_pressure(voltage);  
  
  reading = analogRead(TCondIn_PIN); 
  voltage = get_voltage(reading);  
  CondenserTempIn = get_temperature(voltage);  
  
  reading = analogRead(TCondOut_PIN); 
  voltage = get_voltage(reading);  
  CondenserTempOut = get_temperature(voltage); 

  // append time and sensor data to a data string:
  dataString = String(TimeStamp) + "," + String(CylinderInletPressure, 2) + "," + String(CylinderOutletPressure, 2) + "," +  String(CondenserOutletPressure, 2) + "," + String(CondenserTempIn, 2) + "," + String(CondenserTempOut, 2);   

  // write data to the SD card
  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  File dataFile = SD.open("datalog.txt", FILE_WRITE);

  // if the file is available, write to it:
  if (dataFile) {
    dataFile.println(dataString);
    dataFile.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");
  }
                                                 
  delay(1000); // delay for 50ms before repeating data reading/writing
  
  
}