Arduino GPS Tracker

What You Will Build

You are building a compact GPS data logger. When the tracker is powered on, the GPS module listens for satellite signals. The Arduino reads the GPS serial stream, extracts useful location data, and saves it as a CSV file on the MicroSD card.

After a walk, bike ride, field test, or vehicle trip, you can remove the card and open the log on your computer. The result is a simple but very real location tracking system.

Parts You Need

Recommended Parts List

How GPS Serial Data Works

The GPS module sends a constant stream of text sentences called NMEA data. Those sentences contain time, satellite status, latitude, longitude, speed, altitude, and other values. Reading raw GPS sentences by hand is ugly, so the Arduino sketch uses TinyGPSPlus to parse the data into clean values you can use.

The basic flow is simple:

1. The GPS module sends serial data through its TX pin.
2. The Arduino receives that data on a software serial pin.
3. TinyGPSPlus checks the stream and extracts valid location updates.
4. The SD module writes each valid point to gpslog.csv.

Wiring the GPS Tracker

Wire the project carefully. The GPS module uses serial communication. The MicroSD card uses SPI communication. Keep the wiring neat so you can troubleshoot fast if the SD card or GPS module fails to start.

Install the Arduino Libraries

1. Open the Arduino IDE.
2. Go to Sketch - Include Library - Manage Libraries.
3. Search for TinyGPSPlus and install it.
4. The SD, SPI, and SoftwareSerial libraries are normally already included with the Arduino IDE.

Full Arduino GPS Logger Code

This version reads GPS coordinates, prints them to the Serial Monitor, and saves valid points to a CSV file on the MicroSD card.

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

TinyGPSPlus gps;
SoftwareSerial gpsSerial(4, 3); // GPS TX to D4, GPS RX to D3

const int chipSelect = 10;
File gpsFile;

void setup() {
  Serial.begin(9600);
  gpsSerial.begin(9600);

  Serial.println("Arduino GPS Tracker Starting...");

  if (!SD.begin(chipSelect)) {
    Serial.println("SD card failed. Check wiring and card format.");
    return;
  }

  Serial.println("SD card ready.");

  gpsFile = SD.open("gpslog.csv", FILE_WRITE);
  if (gpsFile) {
    gpsFile.println("Date,Time,Latitude,Longitude,Altitude_m,Speed_kmph,Satellites");
    gpsFile.close();
  }
}

void loop() {
  while (gpsSerial.available() > 0) {
    gps.encode(gpsSerial.read());

    if (gps.location.isUpdated()) {
      logGPSData();
    }
  }
}

void logGPSData() {
  double latitude = gps.location.lat();
  double longitude = gps.location.lng();
  double altitude = gps.altitude.meters();
  double speed = gps.speed.kmph();
  int satellites = gps.satellites.value();

  Serial.print("Latitude: ");
  Serial.println(latitude, 6);
  Serial.print("Longitude: ");
  Serial.println(longitude, 6);
  Serial.print("Satellites: ");
  Serial.println(satellites);
  Serial.println("----------------------");

  gpsFile = SD.open("gpslog.csv", FILE_WRITE);

  if (gpsFile) {
    if (gps.date.isValid()) {
      gpsFile.print(gps.date.month()); gpsFile.print("/");
      gpsFile.print(gps.date.day()); gpsFile.print("/");
      gpsFile.print(gps.date.year());
    } else {
      gpsFile.print("NO_DATE");
    }

    gpsFile.print(",");

    if (gps.time.isValid()) {
      gpsFile.print(gps.time.hour()); gpsFile.print(":");
      gpsFile.print(gps.time.minute()); gpsFile.print(":");
      gpsFile.print(gps.time.second());
    } else {
      gpsFile.print("NO_TIME");
    }

    gpsFile.print(",");
    gpsFile.print(latitude, 6);
    gpsFile.print(",");
    gpsFile.print(longitude, 6);
    gpsFile.print(",");
    gpsFile.print(altitude);
    gpsFile.print(",");
    gpsFile.print(speed);
    gpsFile.print(",");
    gpsFile.println(satellites);

    gpsFile.close();
  } else {
    Serial.println("Could not open gpslog.csv");
  }
}

Portable Power Setup

For the first build, use a USB power bank. It is safer, easy to recharge, and gives you stable 5V power. Once the project works, you can move to a smaller Li-ion battery module and a project enclosure.

Outdoor Field Test

Take the tracker outside, power it on, and give the GPS module time to lock. A cold start can take several minutes. Once it has lock, move around slowly and watch the Serial Monitor. If the latitude and longitude values update, your tracker is working.

1. Power the tracker from the USB battery pack.
2. Wait for GPS lock outdoors.
3. Let it log for at least 5 to 10 minutes.
4. Remove the MicroSD card.
5. Open gpslog.csv on your computer.

Reading the CSV Log

Your CSV file will contain rows of location data. You can open it in a spreadsheet, clean it up, and use the latitude and longitude points with mapping tools.

Troubleshooting

Recommended Video Section

These lightbox videos support the build: NEO-6M GPS setup, Arduino GPS data logging to MicroSD, and a complete Arduino GPS tracker walkthrough.