SDGPSLogger

The SD GPS logger will take data from a GPS and log it into a file on an SD card every 5 seconds.

It is based on the Arduino with an SD card shield and an attached GPS.

Here is the source code:

/*
  SD gps datalogger
  
  This will log locations to a file on an SD card.

  Known bugs:
    If the code writes to the SD card at the same time you power down, it
    can corrupt the file system on the SD card.

  Pins:
    SD MOSI - pin 11
    SD CLK - pin 13
    SD CS - pin 8
    GPS serial out - pin 7
    GPS serial in - pin 6 (not needed)

  SD Shield:
    http://www.sparkfun.com/products/9802
 
  GPS:
    http://www.byonics.com/tinytrak/gps.php (GPS2)
 
  Required Libraries:
    NewSoftSerial - http://arduiniana.org/libraries/newsoftserial/
    TinyGPS - http://arduiniana.org/libraries/tinygps/

Copyright (C) 2011 Jay Sissom

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; version 2
of the License.  THIS SOFTWARE IS RELEASED UNDER THE TERMS OF
VERSION 2 OF THE GPL LICENSE ONLY.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

http://www.gnu.org/licenses/gpl-2.0.html

Jay Sissom jsissom@gmail.com

 */
#include <SD.h>
#include <NewSoftSerial.h>
#include <TinyGPS.h>

// GPS and serial objects
TinyGPS gps;
NewSoftSerial nss(7,6,true);

// GPS data (global so we don't need to pass them around)
long lat, lon;
int year;
byte month, day, hour, minute, second, hundredths;
unsigned long age, date, time, chars, speed;
bool moving = true;

// On the Ethernet Shield, CS is pin 4. Note that even if it's not
// used as the CS pin, the hardware CS pin (10 on most Arduino boards,
// 53 on the Mega) must be left as an output or the SD library
// functions will not work.
const int chipSelect = 8;

void setup() {
  Serial.begin(9600);
  Serial.print("Initializing SD card...");

  // make sure that the default chip select pin is set to
  // output, even if you don't use it:
  pinMode(10, OUTPUT);
  
  // 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.");

  nss.begin(4800);
  
  Serial.println("GPS initialized.");
}

void loop() {
  bool newdata = false;
  unsigned long start = millis();

  // Every 5 seconds we write an update (if we are moving)
  while (millis() - start < 5000) {
    if ( feedgps() ) {
      newdata = true;
    }
  }

  if (newdata) {
    speed = gps.speed();
    gps.get_position(&lat, &lon, &age);
    feedgps();
    gps.get_datetime(&date, &time, &age);
    feedgps();
    gps.crack_datetime(&year, &month, &day, &hour, &minute, &second, &hundredths, &age);
    feedgps();

    // Only write data if we are moving
    if ( moving ) {
      writeData();
    }
    moving = ( speed > 85 );
  } else {
    Serial.println("No GPS data during the last 5 seconds");
  }
}

bool feedgps() {
  while (nss.available()) {
    if (gps.encode(nss.read()))
      return true;
  }
  return false;
}

void writeData() {
  // 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) {
    feedgps();
    dataFile.print(lat);
    dataFile.print("\t");
    dataFile.print(lon);
    dataFile.print("\t");
    dataFile.print(gps.altitude());
    dataFile.print("\t");
    feedgps();
    dataFile.print(year);
    dataFile.print("\t");
    dataFile.print(static_cast<int>(month));
    dataFile.print("\t");
    dataFile.print(static_cast<int>(day));
    dataFile.print("\t");
    dataFile.print(static_cast<int>(hour));
    feedgps();
    dataFile.print("\t");
    dataFile.print(static_cast<int>(minute));
    dataFile.print("\t");
    dataFile.print(static_cast<int>(second));
    dataFile.print("\t");
    dataFile.print(gps.course());
    dataFile.print("\t");
    dataFile.print(speed);
    dataFile.print("\t");
    dataFile.println(age);
    feedgps();
    dataFile.close();
  } else {
    Serial.println("error opening datalog.txt");
  } 

  // print to the serial port too:
  feedgps();
  Serial.print(lat);
  Serial.print("\t");
  Serial.print(lon);
  Serial.print("\t");
  Serial.print(gps.altitude());
  Serial.print("\t");
  feedgps();
  Serial.print(year);
  Serial.print("\t");
  Serial.print(static_cast<int>(month));
  Serial.print("\t");
  Serial.print(static_cast<int>(day));
  Serial.print("\t");
  Serial.print(static_cast<int>(hour));
  feedgps();
  Serial.print("\t");
  Serial.print(static_cast<int>(minute));
  Serial.print("\t");
  Serial.print(static_cast<int>(second));
  Serial.print("\t");
  Serial.print(gps.course());
  Serial.print("\t");
  Serial.print(gps.speed());
  Serial.print("\t");
  Serial.println(age);
  feedgps();
}