ESP32 CYD with LVGL: Build a Sensor Data Table (BME280 + LDR)

/*********
  ESP32 CYD with LVGL - BME280 Sensor Data Table
  Displays temperature, humidity, pressure, LDR, date, time, and IP
  Complete tutorial: https://RandomNerdTutorials.com/esp32-cyd-lvgl-display-bme280-data-table/
*********/

#include <lvgl.h>
#include <TFT_eSPI.h>
#include <XPT2046_Touchscreen.h>
#include <WiFi.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>

// --- CONFIGURATION: YOU MUST EDIT THESE ---
const char* ssid = "YOUR_WIFI_SSID";          // Replace with your Wi-Fi name
const char* password = "YOUR_WIFI_PASSWORD";  // Replace with your Wi-Fi password
const char* timezone = "Europe/Lisbon";       // Replace with your timezone (see list below)
// --- END CONFIGURATION ---

// Common timezone examples:
// "America/New_York", "America/Chicago", "America/Denver", "America/Los_Angeles"
// "Europe/London", "Europe/Paris", "Europe/Berlin", "Europe/Rome"
// "Asia/Tokyo", "Asia/Shanghai", "Asia/Singapore", "Australia/Sydney"

// --- BME280 Configuration ---
#define I2C_SDA 27
#define I2C_SCL 22
#define SEALEVELPRESSURE_HPA (1013.25)
TwoWire I2CBME = TwoWire(0);
Adafruit_BME280 bme;

// Temperature unit: 1 = Celsius, 0 = Fahrenheit
#define TEMP_CELSIUS 1

// --- LDR Pin (built-in) ---
#define LDR_PIN 34

// --- Touchscreen Pins (CYD Standard) ---
#define XPT2046_IRQ 36
#define XPT2046_MOSI 32
#define XPT2046_MISO 39
#define XPT2046_CLK 25
#define XPT2046_CS 33

SPIClass touchscreenSPI = SPIClass(VSPI);
XPT2046_Touchscreen touchscreen(XPT2046_CS, XPT2046_IRQ);

// --- Display Dimensions ---
#define SCREEN_WIDTH 240
#define SCREEN_HEIGHT 320

// Touch coordinates
int touchX, touchY, touchZ;

// LVGL draw buffer
#define DRAW_BUF_SIZE (SCREEN_WIDTH * SCREEN_HEIGHT / 10 * (LV_COLOR_DEPTH / 8))
uint32_t draw_buf[DRAW_BUF_SIZE / 4];

// --- Global Variables for Date/Time ---
String current_date;
String current_time;

// --- LVGL Objects ---
static lv_obj_t * table;
static lv_obj_t * refresh_btn;

// --- Function Declarations ---
void get_date_and_time();
void update_table_values();

// --- LVGL Logging ---
void log_print(lv_log_level_t level, const char * buf) {
  LV_UNUSED(level);
  Serial.println(buf);
  Serial.flush();
}

// --- Touchscreen Read Function for LVGL ---
void touchscreen_read(lv_indev_t * indev, lv_indev_data_t * data) {
  if(touchscreen.tirqTouched() && touchscreen.touched()) {
    TS_Point p = touchscreen.getPoint();

    // --- ADVANCED CALIBRATION (Recommended) ---
    // Replace these with your own values from the calibration guide!
    float alpha_x = -0.000;   // <<< REPLACE WITH YOUR VALUES
    float beta_x = 0.090;      // <<< REPLACE WITH YOUR VALUES
    float delta_x = -33.771;   // <<< REPLACE WITH YOUR VALUES
    float alpha_y = 0.066;     // <<< REPLACE WITH YOUR VALUES
    float beta_y = 0.000;      // <<< REPLACE WITH YOUR VALUES
    float delta_y = -14.632;   // <<< REPLACE WITH YOUR VALUES

    // Apply calibration and clamp to screen bounds
    touchX = alpha_y * p.x + beta_y * p.y + delta_y;
    touchX = constrain(touchX, 0, SCREEN_WIDTH - 1);

    touchY = alpha_x * p.x + beta_x * p.y + delta_x;
    touchY = constrain(touchY, 0, SCREEN_HEIGHT - 1);

    // --- BASIC CALIBRATION (Alternative) ---
    // If you haven't calibrated, uncomment these lines and comment the advanced section above
    // touchX = map(p.x, 200, 3700, 1, SCREEN_WIDTH);
    // touchY = map(p.y, 240, 3800, 1, SCREEN_HEIGHT);
    // touchX = constrain(touchX, 0, SCREEN_WIDTH - 1);
    // touchY = constrain(touchY, 0, SCREEN_HEIGHT - 1);

    touchZ = p.z;

    data->state = LV_INDEV_STATE_PRESSED;
    data->point.x = touchX;
    data->point.y = touchY;

    // Optional debug
    // Serial.printf("Touch: X=%d, Y=%d, Z=%d\n", touchX, touchY, touchZ);
  } else {
    data->state = LV_INDEV_STATE_RELEASED;
  }
}

// --- Fetch Date and Time from WorldTimeAPI ---
void get_date_and_time() {
  HTTPClient http;
  String url = String("http://worldtimeapi.org/api/timezone/") + timezone;
  http.begin(url);
  int httpCode = http.GET();

  if (httpCode == HTTP_CODE_OK) {
    String payload = http.getString();
    JsonDocument doc;
    DeserializationError error = deserializeJson(doc, payload);

    if (!error) {
      const char* datetime = doc["datetime"];
      // Format: "2024-10-15T14:30:45.123456+01:00"
      if (datetime) {
        String dt = String(datetime);
        current_date = dt.substring(0, 10);  // YYYY-MM-DD
        current_time = dt.substring(11, 19); // HH:MM:SS (UTC)
      }
    }
  }
  http.end();
}

// --- Refresh Button Event Handler ---
static void float_button_event_cb(lv_event_t * e) {
  update_table_values();
}

// --- Update All Table Values ---
static void update_table_values(void) {
  // Read BME280
  float temp = bme.readTemperature();
  float hum = bme.readHumidity();
  float pres = bme.readPressure() / 100.0F;

  // Convert temperature if needed
  #if TEMP_CELSIUS
    String temp_str = String(temp) + " °C";
  #else
    temp = temp * 1.8 + 32;
    String temp_str = String(temp) + " °F";
  #endif

  String hum_str = String(hum) + " %";
  String pres_str = String(pres) + " hPa";

  // Read LDR (0-4095)
  String ldr_str = String(analogRead(LDR_PIN));

  // Get fresh time from API
  get_date_and_time();

  // Update table cells
  // Column 0 (labels)
  lv_table_set_cell_value(table, 0, 0, "Data");
  lv_table_set_cell_value(table, 1, 0, "Temperature");
  lv_table_set_cell_value(table, 2, 0, "Humidity");
  lv_table_set_cell_value(table, 3, 0, "Pressure");
  lv_table_set_cell_value(table, 4, 0, "Luminosity");
  lv_table_set_cell_value(table, 5, 0, "Date");
  lv_table_set_cell_value(table, 6, 0, "Time");
  lv_table_set_cell_value(table, 7, 0, "IP Address");

  // Column 1 (values)
  lv_table_set_cell_value(table, 0, 1, "Value");
  lv_table_set_cell_value(table, 1, 1, temp_str.c_str());
  lv_table_set_cell_value(table, 2, 1, hum_str.c_str());
  lv_table_set_cell_value(table, 3, 1, pres_str.c_str());
  lv_table_set_cell_value(table, 4, 1, ldr_str.c_str());
  lv_table_set_cell_value(table, 5, 1, current_date.c_str());
  lv_table_set_cell_value(table, 6, 1, current_time.c_str());
  lv_table_set_cell_value(table, 7, 1, WiFi.localIP().toString().c_str());
}

// --- Draw Event Callback (for cell styling) ---
static void draw_event_cb(lv_event_t * e) {
  lv_draw_task_t * draw_task = lv_event_get_draw_task(e);
  lv_draw_dsc_base_t * base_dsc = (lv_draw_dsc_base_t*) draw_task->draw_dsc;

  if(base_dsc->part == LV_PART_ITEMS) {
    uint32_t row = base_dsc->id1;
    uint32_t col = base_dsc->id2;

    // Center-align the header row (row 0)
    if(row == 0) {
      lv_draw_label_dsc_t * label_draw_dsc = lv_draw_task_get_label_dsc(draw_task);
      if(label_draw_dsc) {
        label_draw_dsc->align = LV_TEXT_ALIGN_CENTER;
      }
    }
  }
}

// --- Create the LVGL User Interface ---
void create_ui() {
  // Create a table
  table = lv_table_create(lv_screen_active());
  lv_obj_set_size(table, 280, 200);
  lv_obj_align(table, LV_ALIGN_CENTER, 0, -10);

  // Set column widths
  lv_table_set_column_width(table, 0, 120);
  lv_table_set_column_width(table, 1, 120);

  // Add custom draw event for styling
  lv_obj_add_event_cb(table, draw_event_cb, LV_EVENT_DRAW_TASK_ADDED, NULL);

  // Create floating refresh button
  refresh_btn = lv_btn_create(lv_screen_active());
  lv_obj_set_size(refresh_btn, 50, 50);
  lv_obj_align(refresh_btn, LV_ALIGN_BOTTOM_RIGHT, -10, -10);
  lv_obj_add_event_cb(refresh_btn, float_button_event_cb, LV_EVENT_CLICKED, NULL);

  // Add refresh icon (simple label with LVGL symbol)
  lv_obj_t * btn_label = lv_label_create(refresh_btn);
  lv_label_set_text(btn_label, LV_SYMBOL_REFRESH);
  lv_obj_center(btn_label);

  // Initial table update
  update_table_values();
}

// --- Initialize BME280 Sensor ---
void initBME() {
  I2CBME.begin(I2C_SDA, I2C_SCL, 100000);
  if (!bme.begin(0x76, &I2CBME)) {
    Serial.println("BME280 not found! Check wiring.");
    while (1);
  }
  Serial.println("BME280 initialized.");
}

// --- Connect to Wi-Fi ---
void connectWiFi() {
  Serial.print("Connecting to Wi-Fi");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected. IP: " + WiFi.localIP().toString());
}

// --- Setup ---
void setup() {
  Serial.begin(115200);
  Serial.println("ESP32 CYD Sensor Data Table Starting...");

  // Connect to Wi-Fi
  connectWiFi();

  // Initialize BME280
  initBME();

  // Initialize touchscreen
  touchscreenSPI.begin(XPT2046_CLK, XPT2046_MISO, XPT2046_MOSI, XPT2046_CS);
  touchscreen.begin(touchscreenSPI);
  touchscreen.setRotation(1); // Landscape orientation

  // Initialize LVGL
  lv_init();
  lv_log_register_print_cb(log_print);

  // Initialize display
  lv_display_t * disp = lv_tft_espi_create(SCREEN_WIDTH, SCREEN_HEIGHT, 
                                            draw_buf, sizeof(draw_buf));
  lv_display_set_rotation(disp, LV_DISPLAY_ROTATION_270);

  // Initialize touch input for LVGL
  lv_indev_t * indev = lv_indev_create();
  lv_indev_set_type(indev, LV_INDEV_TYPE_POINTER);
  lv_indev_set_read_cb(indev, touchscreen_read);

  // Create the UI
  create_ui();

  Serial.println("Ready. Table updates on refresh button press.");
}

// --- Main Loop ---
void loop() {
  lv_task_handler();
  lv_tick_inc(5);
  delay(5);
}