GPS based ELF magnetic measuring system

#include <SoftwareSerial.h>
#include <SPI.h>
#include <SD.h>
#include <TinyGPS.h>

TinyGPS gps;
// The jumpers on the shield set to work with
// these pins, and can be changed if needed.
// create gps object
SoftwareSerial ss(2, 3);

// File for logging data
File rawdata;

const int buttonPin = 2;           // the number of the pushbutton pin
const int ledPin = 8;              // the number of the LED pin

int buttonState = 0;              // variable for reading the pushbutton status

/**************************************************************
Function: setup
Purpose: set up Arduino
Args: none
Returns: nothing
Notes: This function is required by the Arduino
***************************************************************/
void setup()
{
pinMode(buttonPin, INPUT);
// initialize the push button pin as an input
pinMode(buttonPin, OUTPUT);
// initialize the LED as an output

// Serial monitor
Serial.begin(9600);
// baud rate for GPS - 38400 is prefered, but 4800 can also be used
ss.begin(38400);

// Comments from TinyGPS simple_test example
Serial.print("Simple TinyGPS library v. "); Serial.println(TinyGPS::library_version());
Serial.println("by Mikal Hart");
Serial.println();

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

pinMode(10, OUTPUT);
if (!SD.begin(10)) {
Serial.println("...initialization failed!");
}
else
Serial.println("...initialization done.");

}

/**************************************************************
Function: loop
Purpose: loop funtion for Arduino
Args: none
Returns: nothing
Notes: This function is required by the Arduino, and the
Arduino will loop through this function indefinately.

***************************************************************/
void loop(){

bool newData = false;
unsigned long chars;
unsigned short sentences, failed;

// Open data file
File rawdata = SD.open("rawdata.txt", FILE_WRITE);

// For one second we parse GPS data and report some key values

buttonState = digitalRead(buttonPin);         // read the state of the pushbutton value

for (unsigned long start = millis(); millis() - start < 1000;)
{
if(buttonState == HIGH){
// turn LED on
delay(500);
digitalWrite(ledPin, HIGH);
while (ss.available())
{
char c = ss.read();   //GPS data flowing
// Send raw data to the terminal window
Serial.write(c);

// Send raw data to the SD card
if(rawdata)
rawdata.write(c);

if (gps.encode(c))          // if there is a new valid sentence
newData = true;
}
}
// Send manipulate data to the terminal window.
/*
if (newData)
{
float flat, flon;
unsigned long age;
gps.f_get_position(&flat, &flon, &age);
Serial.print("LAT=");
Serial.print(flat == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flat, 6);
Serial.print(" LON=");
Serial.print(flon == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : flon, 6);
Serial.print(" SAT=");
Serial.print(gps.satellites() == TinyGPS::GPS_INVALID_SATELLITES ? 0 : gps.satellites());
Serial.print(" PREC=");
Serial.print(gps.hdop() == TinyGPS::GPS_INVALID_HDOP ? 0 : gps.hdop());
}
*/
// Send a carriage return and close the file
Serial.println("");
rawdata.write("\r");
rawdata.close();
}
}