Building a GPS-Based Weather Station with ESP32, NEO-6M & ST7735 LCD

April 30, 2025 ESP32 Projects

Updated: April 30, 2025

Today, I’m sharing one of my favorite ESP32 projects — a GPS-powered weather station. It’s perfect if you’ve got an ESP32 lying around, a little 1.8" ST7735 TFT screen, and a NEO-6M GPS module. We’ll use your real-time coordinates to fetch live weather data from the free Open-Meteo API, then display it in full color on the LCD. No need to hard-code your city — the GPS does all the work!

This is a fun, real-world IoT project that combines a handful of technologies — GPS, Wi-Fi, APIs, JSON parsing, and good old Arduino code.

Contents

What You’ll Need

Hardware:

ESP32 Dev Board (I used a generic one)
NEO-6M GPS Module
ST7735 1.8" SPI TFT LCD
Breadboard and jumper wires
Power source (USB cable or battery)

Software:

Arduino IDE
Required libraries (we’ll get to that in a sec)

Wiring It Up

Let’s hook up everything. Here’s the connection table:

Module	ESP32 Pin
NEO-6M GPS
TX	GPIO 16
RX	GPIO 17
VCC	3.3V or 5V
GND	GND
ST7735 LCD
CS	GPIO 5
DC	GPIO 2
RST	GPIO 4
MOSI	GPIO 23
SCLK	GPIO 18
VCC	3.3V
GND	GND

📝 Note: The GPS module works best outdoors or near a window. It needs a GPS fix before it can provide coordinates.

The Code

Here's the full code for this project:

<wifi.h><httpclient.h><tinygpsplus.h><hardwareserial.h><adafruit_gfx.h><adafruit_st7735.h><spi.h>#include <WiFi.h>
#include <HTTPClient.h>
#include <TinyGPSPlus.h>
#include <HardwareSerial.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ST7735.h>
#include <SPI.h>
#include <ArduinoJson.h> <arduinojson.h>

// ========== WiFi Credentials ==========
const char* ssid = "YOUR_SSID";
const char* password = "YOUR_PASSWORD";

// ========== GPS Setup ==========
HardwareSerial GPSserial(2); // UART2
TinyGPSPlus gps;

// ========== LCD Setup ==========
#define TFT_CS     5
#define TFT_RST    4
#define TFT_DC     2
#define TFT_SCLK  18
#define TFT_MOSI  23

Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);

// ========== Timing ==========
unsigned long lastUpdate = 0;
const unsigned long updateInterval = 60000; // 60 sec

void setup() {
  Serial.begin(115200);
  GPSserial.begin(9600, SERIAL_8N1, 16, 17); // RX=16, TX=17

  tft.initR(INITR_BLACKTAB);
  tft.fillScreen(ST77XX_BLACK);
  tft.setRotation(1);
  tft.setTextWrap(false);
  tft.setTextColor(ST77XX_WHITE);
  tft.setTextSize(1);
  tft.setCursor(0, 0);
  tft.println("Connecting to WiFi...");

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    tft.print(".");
  }

  tft.println("\nWiFi connected!");
}

void loop() {
  // Continuously read GPS data
  while (GPSserial.available() > 0) {
    gps.encode(GPSserial.read());
  }

  // Check if valid GPS data is available
  if (gps.location.isValid() && millis() - lastUpdate > updateInterval) {
    lastUpdate = millis();
    float latitude = gps.location.lat();
    float longitude = gps.location.lng();

    Serial.printf("GPS: %.6f, %.6f\n", latitude, longitude);
    fetchAndDisplayWeather(latitude, longitude);
  }
}

void fetchAndDisplayWeather(float lat, float lon) {
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    String url = "https://api.open-meteo.com/v1/forecast?latitude=" + 
                 String(lat, 6) + "&longitude=" + String(lon, 6) +
                 "&current_weather=true";

    http.begin(url);
    int httpCode = http.GET();

    if (httpCode > 0) {
      String payload = http.getString();
      Serial.println(payload);

      DynamicJsonDocument doc(1024);
      DeserializationError error = deserializeJson(doc, payload);

      if (!error) {
        float temperature = doc["current_weather"]["temperature"];
        float windspeed = doc["current_weather"]["windspeed"];
        int weathercode = doc["current_weather"]["weathercode"];

        tft.fillScreen(ST77XX_BLACK);
        tft.setCursor(0, 0);
        tft.setTextColor(ST77XX_WHITE);
        tft.setTextSize(1);

        tft.printf("Lat: %.2f\n", lat);
        tft.printf("Lon: %.2f\n", lon);
        tft.printf("Temp: %.1f C\n", temperature);
        tft.printf("Wind: %.1f km/h\n", windspeed);
        tft.printf("Code: %d\n", weathercode);

        displayWeatherIcon(weathercode);
      } else {
        Serial.println("JSON parse failed!");
      }
    } else {
      Serial.println("HTTP request failed.");
    }

    http.end();
  }
}

void displayWeatherIcon(int code) {
  tft.setTextSize(1);
  tft.setTextColor(ST77XX_CYAN);
  tft.setCursor(0, 70);

  // Simplified icon logic
  if (code == 0) {
    tft.println("Clear");
  } else if (code <= 3) {
    tft.println("Partly Cloudy");
  } else if (code <= 45) {
    tft.println("Cloudy");
  } else if (code <= 67) {
    tft.println("Rain");
  } else if (code <= 86) {
    tft.println("Snow");
  } else {
    tft.println("Fog");
  }
}
</arduinojson.h></spi.h></adafruit_st7735.h></adafruit_gfx.h></hardwareserial.h></tinygpsplus.h></httpclient.h></wifi.h>

1. Install Required Libraries

In Arduino IDE, go to Library Manager and install the following:

TinyGPSPlus by Mikal Hart
Adafruit GFX and Adafruit ST7735
ArduinoJson by Benoit Blanchon
HTTPClient (included with ESP32)

2. Setup Wi-Fi

Replace this with your actual credentials:

const char* ssid = "YOUR_SSID";
const char* password = "YOUR_PASSWORD";

3. Upload and Run!

Upload the sketch to your ESP32. Open the Serial Monitor at 115200 baud, and give it a minute or two to get GPS data.

What You’ll See on the LCD

Your real-time GPS coordinates
Current temperature
Wind speed
A simple weather message (Clear, Rainy, etc.)

All this on a colorful, 1.8" TFT screen! Perfect for a portable gadget or even mounting to a bike or backpack.

How It Works

GPS Module gives real-time latitude and longitude.
ESP32 connects to Wi-Fi.
It builds a request to the Open-Meteo API using your location.
Parses the JSON response using
```
ArduinoJson
```
.
Displays the info on the ST7735 LCD.

Why Use GPS?

Because it makes this project location-agnostic — you can carry the device anywhere, and it'll always show the weather for your exact location.

No need to enter a city, zip code, or country. Let the satellites handle it 😄

Possible Upgrades

Add a battery and enclosure to make it portable.
Add alerts or buzzers for extreme weather.
Store weather logs on an SD card.
Switch to ePaper if you want ultra-low power.

Final Thoughts

This project is a great intro to integrating hardware with cloud APIs. I loved seeing live GPS data triggering real-time weather updates. It’s magical how much you can do with just a few modules!

If you build this, I’d love to hear about it. Got stuck somewhere? Just ask!