GPS Logger Shield Hookup Guide

Contributors: jimblom

Example Sketch: TinyGPS Serial Streaming

A couple of our favorite GPS-parsing Arduino libraries are TinyGPS and TinyGPS++. These libraries simplify the task of parsing the excessive NMEA strings, leaving us with just the few bits of data we care about.

You will need to install the libraries in your Arduino IDE. Visit the links above to download them. Reference our Installing an Arduino Library tutorial for any additional library-installing help you may need.

TinyGPS++ Example

Here's a quick example, which uses the TinyGPS++ library to parse NMEA strings for position, altitude, time, and date. Copy and past the code below into your Arduino IDE and upload to your board.

language:c
/******************************************************************************
  TinyGPSPlus_GPS_Shield.ino
  TinyGPS++ Library Example for the SparkFun GPS Logger Shield
  By Jim Lindblom @ SparkFun Electronics
  February 9, 2016
  https://github.com/sparkfun/GPS_Shield

  This example uses SoftwareSerial to communicate with the GPS module on
  pins 8 and 9. It uses the TinyGPS++ library to parse the NMEA strings sent
  by the GPS module, and prints interesting GPS information to the serial
  monitor.

  After uploading the code, open your serial monitor, set it to 9600 baud, and
  watch for latitude, longitude, altitude, course, speed, date, time, and the
  number of visible satellites.

  Resources:
  TinyGPS++ Library  - https://github.com/mikalhart/TinyGPSPlus/releases
  SoftwareSerial Library

  Development/hardware environment specifics:
  Arduino IDE 1.6.7
  GPS Logger Shield v2.0 - Make sure the UART switch is set to SW-UART
  Arduino Uno, RedBoard, Pro, etc.
******************************************************************************/

#include <TinyGPS++.h> // Include the TinyGPS++ library
TinyGPSPlus tinyGPS; // Create a TinyGPSPlus object

#define GPS_BAUD 9600 // GPS module baud rate. GP3906 defaults to 9600.

// If you're using an Arduino Uno, RedBoard, or any board that uses the
// 0/1 UART for programming/Serial monitor-ing, use SoftwareSerial:
#include <SoftwareSerial.h>
#define ARDUINO_GPS_RX 9 // GPS TX, Arduino RX pin
#define ARDUINO_GPS_TX 8 // GPS RX, Arduino TX pin
SoftwareSerial ssGPS(ARDUINO_GPS_TX, ARDUINO_GPS_RX); // Create a SoftwareSerial

// Set gpsPort to either ssGPS if using SoftwareSerial or Serial1 if using an
// Arduino with a dedicated hardware serial port
#define gpsPort ssGPS  // Alternatively, use Serial1 on the Leonardo

// Define the serial monitor port. On the Uno, and Leonardo this is 'Serial'
//  on other boards this may be 'SerialUSB'
#define SerialMonitor Serial

void setup()
{
  SerialMonitor.begin(9600);
  gpsPort.begin(GPS_BAUD);
}

void loop()
{
  // print position, altitude, speed, time/date, and satellites:
  printGPSInfo();

  // "Smart delay" looks for GPS data while the Arduino's not doing anything else
  smartDelay(1000); 
}

void printGPSInfo()
{
  // Print latitude, longitude, altitude in feet, course, speed, date, time,
  // and the number of visible satellites.
  SerialMonitor.print("Lat: "); SerialMonitor.println(tinyGPS.location.lat(), 6);
  SerialMonitor.print("Long: "); SerialMonitor.println(tinyGPS.location.lng(), 6);
  SerialMonitor.print("Alt: "); SerialMonitor.println(tinyGPS.altitude.feet());
  SerialMonitor.print("Course: "); SerialMonitor.println(tinyGPS.course.deg());
  SerialMonitor.print("Speed: "); SerialMonitor.println(tinyGPS.speed.mph());
  SerialMonitor.print("Date: "); printDate();
  SerialMonitor.print("Time: "); printTime();
  SerialMonitor.print("Sats: "); SerialMonitor.println(tinyGPS.satellites.value());
  SerialMonitor.println();
}

// This custom version of delay() ensures that the tinyGPS object
// is being "fed". From the TinyGPS++ examples.
static void smartDelay(unsigned long ms)
{
  unsigned long start = millis();
  do
  {
    // If data has come in from the GPS module
    while (gpsPort.available())
      tinyGPS.encode(gpsPort.read()); // Send it to the encode function
    // tinyGPS.encode(char) continues to "load" the tinGPS object with new
    // data coming in from the GPS module. As full NMEA strings begin to come in
    // the tinyGPS library will be able to start parsing them for pertinent info
  } while (millis() - start < ms);
}

// printDate() formats the date into dd/mm/yy.
void printDate()
{
  SerialMonitor.print(tinyGPS.date.day());
  SerialMonitor.print("/");
  SerialMonitor.print(tinyGPS.date.month());
  SerialMonitor.print("/");
  SerialMonitor.println(tinyGPS.date.year());
}

// printTime() formats the time into "hh:mm:ss", and prints leading 0's
// where they're called for.
void printTime()
{
  SerialMonitor.print(tinyGPS.time.hour());
  SerialMonitor.print(":");
  if (tinyGPS.time.minute() < 10) SerialMonitor.print('0');
  SerialMonitor.print(tinyGPS.time.minute());
  SerialMonitor.print(":");
  if (tinyGPS.time.second() < 10) SerialMonitor.print('0');
  SerialMonitor.println(tinyGPS.time.second());
}

You may need to adjust the gpsPort and SerialMonitor defines near the top of the sketch. As it is, the sketch is set up to use the SoftwareSerial port.

After uploading the code, open up your serial monitor to watch the parsed GPS data stream by.

If your module doesn't have a good GPS fix, you'll probably see a lot of 0's stream by; the time should be incrementing, although it'll be incorrect (unless you plugged your Arduino in at exactly midnight!).

If you can find a way to take your computer and Arduino setup outside, that'll be your best bet for getting a fix. Otherwise, try to take it near an open window. The better view it has of the sky, the better chance it'll have to find the four satellites it needs.

A successful, fixed GPS stream will look something like this:

Lat: 40.090422
Long: -105.184534
Alt: 5243.77
Course: 295.56
Speed: 0.01
Date: 26/1/2016
Time: 20:19:34
Sats: 6

For more information on using the TinyGPS++ Library, check out the project homepage.