USB GPS Dashboard

#include <Arduino.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
#include <TinyGPS++.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_HMC5883_U.h>


// Forward declarations
uint16_t backgroundColor();
uint16_t foregroundColor();
uint16_t accentColor();
String twoDigits(uint8_t value);
bool isLeapYear(int year);
uint8_t daysInMonth(int year, uint8_t month);
void addOneDay(int &year, uint8_t &month, uint8_t &day);
uint8_t weekDay(int year, uint8_t month, uint8_t day);
uint8_t lastSunday(int year, uint8_t month);
bool pragueSummerTime(int year, uint8_t month, uint8_t day, uint8_t hourUtc);
String localDateTimeText();
String directionFromDegrees(float value);
String temperatureText();
String speedText();
String altitudeText();
String headingText();
void printClipped(const String &text, int16_t x, int16_t y, uint8_t size, int16_t maxWidth);
void printClippedScaled(const String &text, int16_t x, int16_t y, uint8_t widthSize, uint8_t heightSize, int16_t maxWidth);
void printCompressedTall(const String &text, int16_t x, int16_t y, uint8_t heightSize, int16_t maxWidth);
void drawStaticLayout();
void drawValues();
void redrawScreen();
void updateHeading();
void updateTemperature();
void handleButtons();

constexpr int TFT_CS_PIN = 27;
constexpr int TFT_DC_PIN = 32;
constexpr int TFT_RST_PIN = 33;
constexpr int GPS_RX_PIN = 16;
constexpr int ONEWIRE_PIN = 13;
constexpr int BUTTON_PIN = 14;
constexpr int ROTATE_BUTTON_PIN = 4;
constexpr int I2C_SDA_PIN = 21;
constexpr int I2C_SCL_PIN = 22;

Adafruit_ILI9341 tft(TFT_CS_PIN, TFT_DC_PIN, TFT_RST_PIN);
TinyGPSPlus gps;
HardwareSerial gpsSerial(2);
OneWire oneWire(ONEWIRE_PIN);
DallasTemperature temperatureSensor(&oneWire);
Adafruit_HMC5883_Unified compass(12345);

bool nightMode = false;
bool compassReady = false;
bool temperaturePending = false;
float outsideTempC = NAN;
float headingDegrees = NAN;
uint8_t displayRotation = 3; // Starts wide; each rotate-button press advances one quarter-turn clockwise.
unsigned long lastScreenUpdate = 0;
unsigned long lastTemperatureRequest = 0;
unsigned long lastModeButtonChange = 0;
unsigned long lastRotateButtonChange = 0;
bool lastModeReading = HIGH, modeButtonState = HIGH;
bool lastRotateReading = HIGH, rotateButtonState = HIGH;

uint16_t backgroundColor() { return nightMode ? ILI9341_BLACK : ILI9341_WHITE; }
uint16_t foregroundColor() { return nightMode ? ILI9341_GREEN : ILI9341_BLACK; }
uint16_t accentColor() { return nightMode ? ILI9341_CYAN : ILI9341_BLUE; }
String twoDigits(uint8_t value) { return value < 10 ? "0" + String(value) : String(value); }
bool isLeapYear(int year) { return (year % 4 == 0 && year % 100 != 0) || year % 400 == 0; }
uint8_t daysInMonth(int year, uint8_t month) { static const uint8_t days[] = {31,28,31,30,31,30,31,31,30,31,30,31}; return month == 2 && isLeapYear(year) ? 29 : days[month - 1]; }
void addOneDay(int &year, uint8_t &month, uint8_t &day) { if (++day > daysInMonth(year, month)) { day = 1; if (++month > 12) { month = 1; ++year; } } }
uint8_t weekDay(int year, uint8_t month, uint8_t day) { static const int offsets[] = {0,3,2,5,0,3,5,1,4,6,2,4}; int y = year - (month < 3); return (y + y / 4 - y / 100 + y / 400 + offsets[month - 1] + day) % 7; }
uint8_t lastSunday(int year, uint8_t month) { uint8_t day = daysInMonth(year, month); return day - weekDay(year, month, day); }
bool pragueSummerTime(int year, uint8_t month, uint8_t day, uint8_t hourUtc) { if (month < 3 || month > 10) return false; if (month > 3 && month < 10) return true; uint8_t change = lastSunday(year, month); return month == 3 ? (day > change || (day == change && hourUtc >= 1)) : (day < change || (day == change && hourUtc < 1)); }

String localDateTimeText() {
#if !defined(ESP32)
  // The browser has no GPS receiver, so use a fixed example only in its preview.
  return "26.09.2026 Sat 14:30";
#else
  if (!gps.date.isValid() || !gps.time.isValid()) return "Waiting for GPS time";
  int year = gps.date.year(); uint8_t month = gps.date.month(), day = gps.date.day(), hour = gps.time.hour();
  hour += pragueSummerTime(year, month, day, hour) ? 2 : 1;
  if (hour >= 24) { hour -= 24; addOneDay(year, month, day); }
  static const char *names[] = {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
  return twoDigits(day) + "." + twoDigits(month) + "." + String(year) + " " + names[weekDay(year, month, day)] + " " + twoDigits(hour) + ":" + twoDigits(gps.time.minute());
#endif
}
String directionFromDegrees(float value) { if (isnan(value)) return "---"; static const char* names[] = {"N","NE","E","SE","S","SW","W","NW"}; return names[(int)((value + 22.5f) / 45.0f) % 8]; }
String temperatureText() {
#if !defined(ESP32)
  return "18.6 C";
#else
  return isnan(outsideTempC) || outsideTempC <= -126 ? "--.- C" : String(outsideTempC, 1) + " C";
#endif
}
String speedText() {
#if !defined(ESP32)
  return "68 km/h";
#else
  return gps.speed.isValid() ? String((int)round(gps.speed.kmph())) + " km/h" : "--- km/h";
#endif
}
String altitudeText() {
#if !defined(ESP32)
  return "245 m";
#else
  return gps.altitude.isValid() ? String((int)round(gps.altitude.meters())) + " m" : "---- m";
#endif
}
String headingText() {
#if !defined(ESP32)
  return "72 NE";
#else
  return isnan(headingDegrees) ? "---" : String((int)round(headingDegrees)) + " " + directionFromDegrees(headingDegrees);
#endif
}

void printClipped(const String &text, int16_t x, int16_t y, uint8_t size, int16_t maxWidth) {
  tft.setTextSize(size);
  String shown = text;
  while (shown.length() && (int16_t)(shown.length() * 6 * size) > maxWidth) shown = shown.substring(0, shown.length() - 1);
  tft.setCursor(x, y);
  tft.print(shown);
}

// Scale built-in text independently in each direction, clipping only if it cannot fit.
void printClippedScaled(const String &text, int16_t x, int16_t y, uint8_t widthSize, uint8_t heightSize, int16_t maxWidth) {
  tft.setTextSize(widthSize, heightSize);
  String shown = text;
  while (shown.length() && (int16_t)(shown.length() * 6 * widthSize) > maxWidth) shown = shown.substring(0, shown.length() - 1);
  tft.setCursor(x, y);
  tft.print(shown);
}

// The standard font has a blank column at each glyph edge.  Let adjacent letters share
// that blank space so this line can be wider without losing any date or time characters.
void printCompressedTall(const String &text, int16_t x, int16_t y, uint8_t heightSize, int16_t maxWidth) {
  const int16_t characterAdvance = 11;
  const int16_t count = min((int16_t)text.length(), (int16_t)(maxWidth / characterAdvance));
  tft.setTextSize(2, heightSize);
  for (int16_t i = 0; i < count; ++i) {
    char character[2] = { text[i], '\0' };
    tft.setCursor(x + i * characterAdvance, y);
    tft.print(character);
  }
}

void drawStaticLayout() {
  const int w = tft.width(), h = tft.height();
  const bool wide = w > h;
  const uint16_t bg = backgroundColor(), accent = accentColor();
  tft.fillScreen(bg);
  tft.setTextWrap(false);
  tft.drawRoundRect(2, 2, w - 4, h - 4, 7, accent);
  tft.setTextColor(accent, bg);
  tft.setTextSize(1);
  if (wide) {
    tft.drawFastHLine(7, 68, w - 14, accent);
    tft.drawFastHLine(7, 151, w - 14, accent);
    tft.setCursor(10, 10); tft.print("PRAGUE LOCAL TIME");
    tft.setCursor(w - 45, 10); tft.print(nightMode ? "NIGHT" : "DAY");
    tft.setCursor(10, 78); tft.print("SPEED"); tft.setCursor(w / 2 + 12, 78); tft.print("HEADING");
    tft.setCursor(10, 161); tft.print("ALTITUDE"); tft.setCursor(w / 2 + 12, 161); tft.print("OUTSIDE");
  } else {
    // Compact 4:3 view: use the entire panel as three equal information rows.
    const int row1 = h / 3, row2 = (h * 2) / 3;
    const int dividerX = w / 2;
    tft.drawFastHLine(6, row1, w - 12, accent);
    tft.drawFastHLine(6, row2, w - 12, accent);
    tft.drawFastVLine(dividerX, row1 + 14, row2 - row1 - 28, accent);
    tft.drawFastVLine(dividerX, row2 + 14, h - row2 - 28, accent);
    tft.setCursor(8, row1 + 8); tft.print("SPEED");
    tft.setCursor(dividerX + 8, row1 + 8); tft.print("HEADING");
    tft.setCursor(8, row2 + 8); tft.print("ALTITUDE");
    tft.setCursor(dividerX + 8, row2 + 8); tft.print("TEMP");
  }
}

void drawValues() {
  const int w = tft.width(), h = tft.height();
  const bool wide = w > h;
  const uint16_t bg = backgroundColor(), fg = foregroundColor();
  tft.setTextColor(fg, bg);
  if (wide) {
    tft.fillRect(8, 24, w - 16, 38, bg);
    tft.fillRect(8, 94, w / 2 - 12, 44, bg); tft.fillRect(w / 2 + 8, 94, w / 2 - 16, 44, bg);
    tft.fillRect(8, 177, w / 2 - 12, 44, bg); tft.fillRect(w / 2 + 8, 177, w / 2 - 16, 44, bg);
    printClipped(localDateTimeText(), 10, 34, 2, w - 20);
    printClipped(speedText(), 10, 105, 3, w / 2 - 18);
    printClipped(headingText(), w / 2 + 12, 105, 3, w / 2 - 20);
    printClipped(altitudeText(), 10, 188, 3, w / 2 - 18);
    printClipped(temperatureText(), w / 2 + 12, 188, 3, w / 2 - 20);
  } else {
    const int row1 = h / 3, row2 = (h * 2) / 3;
    const int dividerX = w / 2;
    // Erase only changing text; the row separators and vertical dividers remain visible.
    tft.fillRect(7, 7, w - 14, row1 - 14, bg);
    tft.fillRect(7, row1 + 22, dividerX - 15, row2 - row1 - 29, bg);
    tft.fillRect(dividerX + 7, row1 + 22, w - dividerX - 14, row2 - row1 - 29, bg);
    tft.fillRect(7, row2 + 22, dividerX - 15, h - row2 - 29, bg);
    tft.fillRect(dividerX + 7, row2 + 22, w - dividerX - 14, h - row2 - 29, bg);
    // The top panel is the TODAY area: a clear title plus tall date, day, and time.
    // The built-in font keeps the browser preview and real ESP32 display consistent.
    tft.setTextColor(accentColor(), bg);
    tft.setTextSize(2);
    tft.setCursor(8, 12);
    tft.print("TODAY");
    tft.setTextColor(fg, bg);
    printCompressedTall(localDateTimeText(), 8, 53, 4, w - 16);
    // Larger, taller readings make full use of the two lower information rows.
    printClippedScaled(speedText(), 8, row1 + 38, 2, 3, dividerX - 16);
    printClippedScaled(headingText(), dividerX + 8, row1 + 38, 2, 3, w - dividerX - 16);
    printClippedScaled(altitudeText(), 8, row2 + 38, 2, 3, dividerX - 16);
    printClippedScaled(temperatureText(), dividerX + 8, row2 + 38, 2, 3, w - dividerX - 16);
  }
}

void redrawScreen() { tft.setRotation(displayRotation); drawStaticLayout(); drawValues(); }
void updateHeading() { if (!compassReady) return; sensors_event_t event; compass.getEvent(&event); float angle = atan2(event.magnetic.y, event.magnetic.x) * 180.0f / PI; headingDegrees = angle < 0 ? angle + 360.0f : angle; }
void updateTemperature() { unsigned long now = millis(); if (!temperaturePending && now - lastTemperatureRequest >= 1000) { temperatureSensor.requestTemperatures(); temperaturePending = true; lastTemperatureRequest = now; } if (temperaturePending && now - lastTemperatureRequest >= 800) { float value = temperatureSensor.getTempCByIndex(0); if (value > -126) outsideTempC = value; temperaturePending = false; } }

void handleButtons() {
  bool modeReading = digitalRead(BUTTON_PIN);
  if (modeReading != lastModeReading) lastModeButtonChange = millis();
  if (millis() - lastModeButtonChange > 35 && modeReading != modeButtonState) { modeButtonState = modeReading; if (modeButtonState == LOW) { nightMode = !nightMode; redrawScreen(); } }
  lastModeReading = modeReading;
  bool rotateReading = digitalRead(ROTATE_BUTTON_PIN);
  if (rotateReading != lastRotateReading) lastRotateButtonChange = millis();
  if (millis() - lastRotateButtonChange > 35 && rotateReading != rotateButtonState) { rotateButtonState = rotateReading; if (rotateButtonState == LOW) { displayRotation = (displayRotation + 1) % 4; redrawScreen(); } }
  lastRotateReading = rotateReading;
}

void setup() {
  pinMode(BUTTON_PIN, INPUT_PULLUP); pinMode(ROTATE_BUTTON_PIN, INPUT_PULLUP);
  Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN); gpsSerial.begin(9600, SERIAL_8N1, GPS_RX_PIN, -1);
  tft.begin(); temperatureSensor.begin(); temperatureSensor.setWaitForConversion(false); compassReady = compass.begin(); redrawScreen();
}
void loop() {
  while (gpsSerial.available()) gps.encode(gpsSerial.read());
  handleButtons(); updateTemperature();
  if (millis() - lastScreenUpdate >= 1000) { updateHeading(); drawValues(); lastScreenUpdate = millis(); }
}