Part 5: Software & Code

Learning Objectives

• Install Arduino IDE
• Install required libraries
• Upload and run GPS code
• Understand NMEA sentences

Step 1: Choose Your Arduino Environment

You have two options for programming your Arduino. Choose whichever works best for you:

The Arduino Cloud interface - click "Create New" to start a new sketch.

☁️ For Arduino Cloud Users: Connect Your Device

If you're using Arduino Cloud, you need to connect your Arduino board:

1. Plug your Arduino into your computer via USB
2. Click on "Devices" in the left sidebar
3. Follow the prompts to add your device

Click "Devices" to connect your Arduino

The wizard will guide you through three simple steps:

The device setup wizard - click "Add Device" and follow the prompts!

When prompted, choose "Automatic Setup" and select "Arduino boards":

Select "Automatic Setup" → "Arduino boards" for the easiest configuration.

Then select "Via Serial (USB)" to connect your board:

Choose "Via Serial (USB)" for the standard USB cable connection.

Click "Install" if you see this prompt - it's a one-time setup!

Follow the installation wizard - accept the defaults and click Next through the steps:

Open the downloaded file and follow the wizard.

Click Finish when complete. You should see "Your Agent is ready":

Click "Finish" and you're all set!

Once installed, the Cloud platform will detect your board automatically. Select it from the list:

Your Arduino UNO R4 WiFi should appear in the list - click to select it!

Wait while the device pairs (this may take up to 30 seconds):

Pairing in progress - please wait...

You should see confirmation that your device is connected. Click Continue:

"Arduino UNO R4 WiFi connected" - Click Continue to finish setup!

If prompted, allow the board to update. This takes a few minutes - keep the device connected:

The update is automatic - just wait for it to complete.

If asked, unplug and replug the board to finalize the firmware update:

Unplug the USB cable, wait a moment, then plug it back in.

You should see the success confirmation. Make sure your device LED is solid (not blinking):

"Arduino UNO R4 WiFi connected" with solid LED = ready to go! Click Continue.

Finally, configure the device by giving it a name (e.g., "GPS Unit"). Click the checkmark when done:

Name your device (e.g., "GPS Unit") and click the checkmark.

Step 2: Install the TinyGPS++ Library

We need the TinyGPS++ library to parse GPS data. Choose the method that matches your environment:

💻 For Desktop Arduino IDE:

1. Open Arduino IDE
2. Go to Sketch → Include Library → Manage Libraries
3. Search for "TinyGPSPlus" by Mikal Hart
4. Click Install

☁️ For Arduino Cloud:

1. Click the Libraries icon (📚) in the left sidebar
2. Search for "TinyGPSPlus" or "TinyGPS++"
3. Click Include to add it to your sketch

Step 3: The GPS Code

💻 For Desktop IDE (Serial Monitor Test): Copy and paste this code to test your GPS and see output in the Serial Monitor:

/*
 * GPS Workshop - ISU MSS26
 * Building and Testing GPS Units
 *
 * This code reads GPS data from a NEO-6M module
 * using the Hardware Serial port (Serial1) on the Arduino Uno R4 WiFi
 *
 * Wiring:
 *   GPS TX  -> Arduino Pin 0 (RX)
 *   GPS RX  -> Arduino Pin 1 (TX)
 *   GPS VCC -> Arduino 5V
 *   GPS GND -> Arduino GND
 */

#include <TinyGPS++.h>

// The TinyGPS++ object
TinyGPSPlus gps;

void setup() {
  // Start the Serial Monitor (laptop)
  Serial.begin(9600);
  
  // Start the hardware serial port for the GPS (Pins 0 and 1)
  // Most NEO-6M modules use 9600 baud by default
  Serial1.begin(9600);

  Serial.println(F("===================================="));
  Serial.println(F("  GPS Workshop - ISU MSS26"));
  Serial.println(F("  Hardware: Arduino Uno R4 WiFi"));
  Serial.println(F("===================================="));
  Serial.println();
  Serial.println(F("Searching for satellites..."));
}

void loop() {
  // Read data from the GPS module on Serial1
  while (Serial1.available() > 0) {
    if (gps.encode(Serial1.read())) {
      displayInfo();
    }
  }

  // Check if GPS is detected (if 5 seconds pass with no data)
  if (millis() > 5000 && gps.charsProcessed() < 10) {
    Serial.println(F("ERROR: No GPS detected. Check wiring (Pins 0 & 1)!"));
    delay(5000);
  }
}

void displayInfo() {
  Serial.println(F("----------------------------------------"));

  // Location
  Serial.print(F("Location:  "));
  if (gps.location.isValid()) {
    Serial.print(gps.location.lat(), 6);
    Serial.print(F(", "));
    Serial.print(gps.location.lng(), 6);
  } else {
    Serial.print(F("INVALID (Searching for satellites...)"));
  }
  Serial.println();

  // Date and Time
  Serial.print(F("Date/Time: "));
  if (gps.date.isValid() && gps.time.isValid()) {
    Serial.print(gps.date.month());
    Serial.print(F("/"));
    Serial.print(gps.date.day());
    Serial.print(F("/"));
    Serial.print(gps.date.year());
    Serial.print(F(" "));
    if (gps.time.hour() < 10) Serial.print(F("0"));
    Serial.print(gps.time.hour());
    Serial.print(F(":"));
    if (gps.time.minute() < 10) Serial.print(F("0"));
    Serial.print(gps.time.minute());
    Serial.print(F(" UTC"));
  } else {
    Serial.print(F("INVALID"));
  }
  Serial.println();

  // Satellites & Quality
  Serial.print(F("Satellites: "));
  Serial.print(gps.satellites.value());
  Serial.print(F("  |  HDOP: "));
  Serial.println(gps.hdop.hdop());

  Serial.println(F("----------------------------------------"));
  Serial.println();
}

☁️ For Arduino Cloud (IoT Dashboard):

If you're using Arduino Cloud, first create a "Thing" with these variables:

• latitude - Floating Point Number (Read Only)
• longitude - Floating Point Number (Read Only)
• altitude - Floating Point Number (Read Only)
• satellites - Integer (Read Only)
• gps_time - Character String (Read Only)

Then use this code in your Cloud sketch:

/* 
  GPS Workshop - Arduino IoT Cloud Version
  Config: Hardware Serial1 on Pins 0 & 1
*/

#include "thingProperties.h"
#include <TinyGPS++.h>

// The TinyGPS++ object
TinyGPSPlus gps;

// Timer for GPS updates (don't flood the cloud)
unsigned long lastUpdate = 0;
const unsigned long UPDATE_INTERVAL = 2000; // Update every 2 seconds

void setup() {
  // Initialize serial for monitor
  Serial.begin(9600);
  delay(1500); 

  // Start the Hardware Serial port for the GPS (Pins 0 and 1)
  Serial1.begin(9600);

  Serial.println(F("===================================="));
  Serial.println(F("  GPS Workshop - IoT Cloud Version"));
  Serial.println(F("  Config: Pins 0 & 1 (Hardware Serial)"));
  Serial.println(F("===================================="));
  Serial.println();

  // Defined in thingProperties.h
  initProperties();
  ArduinoCloud.begin(ArduinoIoTPreferredConnection);
  setDebugMessageLevel(2);
  ArduinoCloud.printDebugInfo();
  
  Serial.println(F("Searching for GPS satellites..."));
}

void loop() {
  ArduinoCloud.update();
  
  // Read data from the GPS module on Serial1
  while (Serial1.available() > 0) {
    char c = Serial1.read();
    if (gps.encode(c)) {
      // Only update cloud every 2 seconds
      if (millis() - lastUpdate >= UPDATE_INTERVAL) {
        updateGPSData();
        lastUpdate = millis();
      }
    }
  }

  // DIAGNOSTIC LOOP - Check for errors every 5 seconds
  if (millis() > 5000 && millis() - lastUpdate > 5000) {
    if (gps.charsProcessed() < 10) {
      Serial.println(F("ERROR: No GPS data received! Check wiring."));
      Serial.println(F("       GPS TX -> Arduino Pin 0"));
      Serial.println(F("       GPS RX -> Arduino Pin 1"));
    } else if (gps.sentencesWithFix() == 0) {
      Serial.print(F("DIAGNOSTIC: connected ("));
      Serial.print(gps.charsProcessed());
      Serial.println(F(" bytes). Waiting for fix... (Go outside!)"));
    }
    lastUpdate = millis();
  }
}

void updateGPSData() {
  if (gps.location.isValid()) {
    latitude = gps.location.lat();
    longitude = gps.location.lng();
    altitude = gps.altitude.meters();
    satellites = gps.satellites.value();
    
    char timeBuffer[10];
    sprintf(timeBuffer, "%02d:%02d:%02d", 
            gps.time.hour(), gps.time.minute(), gps.time.second());
    gps_time = String(timeBuffer);
  }
}

Step 4: Upload the Code

💻 For Desktop Arduino IDE:

1. Connect your Arduino to the computer via USB.
2. Go to Tools → Board and select Arduino Uno R4 WiFi.
3. Go to Tools → Port and select the COM port that appears.
4. Click the Upload Button (the Right Arrow icon `→`) at the top left.
5. Wait for the message "Done uploading" at the bottom.

☁️ For Arduino Cloud:

1. Ensure the Arduino Create Agent is running on your computer.
2. Check that your board (Arduino Uno R4 WiFi) is selected in the top bar.
3. Click the Upload Button (the Right Arrow icon `→`) located near the top right.
4. Wait for the console to say "Success" or "Uploaded".
5. Click the Monitor tab to check for the "DIAGNOSTIC" messages!

Step 5: View Your Data

For Serial Monitor (Debugging):

1. Open Tools → Serial Monitor (or the Monitor tab in Cloud).
2. Set baud rate to 9600 (bottom right corner).
3. Check Diagnostics: If it says "No GPS data received", check your wiring!
4. If it says "Waiting for fix...", take the unit outside.

For Arduino Cloud Dashboard:

1. Once the Monitor shows a fix, go to your Dashboards tab.
2. Add a Map Widget and link it to `latitude` and `longitude`.
3. Add Gauges for `satellites` and `altitude`.
4. Watch your real-time position appear on the map! 🌍

Troubleshooting: "No GPS Data Received"

If your Serial Monitor shows a repeating error like the one below, your Arduino cannot "hear" the GPS module.

How to Fix It:

1. Check Power (No Light?): Look at the GPS board. Is the small LED on? If not, check your VCC (5V) and GND wires. The GPS needs power!
2. Swap TX/RX: This is the most common issue. Swap the wires on Pin 0 and Pin 1. (GPS TX must go to Arduino RX).
3. Check Solder: If you are using a new module, ensure the headers are soldered on, not just loose.

Understanding NMEA Sentences

GPS modules output data in NMEA format. Common sentences:

Example NMEA Sentence

Troubleshooting