Initial TableWatch implementation

2026-01-18 21:33:13 +02:00
commit 15c84487ec
20 changed files with 1261 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,5 @@
+.pio
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch
--- a/.vscode/extensions.json
+++ b/.vscode/extensions.json
@@ -0,0 +1,10 @@
+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
+    ]
+}
--- a/README.md
+++ b/README.md
@@ -0,0 +1,101 @@
+# ElinkInformer / TableWatch
+
+E‑paper інформер на ESP32‑S3 (WeActStudio 2.9" tri‑color). Показує час великими цифрами, Wi‑Fi, батарею, погоду та дані з Notion. Є веб‑інтерфейс для керування інтервалами, а також оновлення прошивки через браузер.
+
+## Функції
+- великий годинник у стилі flip‑card
+- статус‑бар: Wi‑Fi, батарея, погода, час
+- таблиця Notion (5 записів) з полями `Name` + `Data/Date`
+- чергування екранів (час/Notion) з налаштовуваними інтервалами
+- Wi‑Fi portal налаштування (SSID `ElinkInformer-Setup`)
+- веб‑інтерфейс з Bootstrap‑темою (mDNS `tablewatch.local`)
+- оновлення прошивки через web upload
+
+## Обладнання
+- ESP32‑S3 (board: `esp32-s3-zero` у PlatformIO)
+- WeActStudio 2.9" E‑Paper (GxEPD2_290_C90c)
+
+## Піни дисплея
+У `src/config.h`:
+- `PIN_BUSY = 6`
+- `PIN_RST = 7`
+- `PIN_DC = 8`
+- `PIN_CS = 9`
+- `PIN_SCK = 10`
+- `PIN_MOSI = 11`
+
+## Батарея / ADC
+Налаштування в `src/config.h`:
+- `kBatteryAdcPin` (за замовчуванням `A0`)
+- `kBatteryAdcRefMv` (3300 мВ)
+- `kBatteryDividerNum`/`kBatteryDividerDen` (коефіцієнт подільника)
+- `kBatteryMvMin`/`kBatteryMvMax` (межі 0–100%)
+
+Калібруйте `kBatteryMvMin`/`kBatteryMvMax` під вашу батарею.
+
+## Погода
+- Джерело: Open‑Meteo (`kWeatherUrl`)
+- Відображення: `Дніпро +3C дощ` (українські назви)
+
+## Notion
+- Використовується Notion API для читання бази.
+- Потрібні поля в базі:
+  - `Name` (title)
+  - `Data` або `Date` або `Дата` (date)
+- ID бази береться з URL (параметр `v` не потрібен).
+- Токен інтеграції збережений у `kNotionToken`.
+
+**Важливо:** інтеграцію потрібно додати до доступу бази (Share → додати інтеграцію).
+
+## Веб‑інтерфейс
+Доступ за адресою `http://tablewatch.local/` (mDNS) або IP.
+
+Можна налаштувати:
+- час показу екрана годинника
+- час показу екрана Notion
+- інтервал мережевої синхронізації
+
+Кнопки:
+- Оновлення прошивки (завантаження `.bin`)
+- Перезавантаження
+
+## Оновлення прошивки (Web)
+Використовуйте файл `.bin` після збірки:
+```bash
+pio run
+```
+Файл з’явиться у `.pio/build/esp32-s3-devkitm-1/firmware.bin`.
+
+## Збірка та прошивка (USB)
+```bash
+pio run
+pio run -t upload
+```
+
+## Налаштування Wi‑Fi
+Після старту пристрій піднімає portal:
+- SSID: `ElinkInformer-Setup`
+- Відкрити `192.168.4.1`
+
+## Налаштування інтервалів
+Параметри зберігаються в RTC:
+- `gClockScreenSec` — екран часу
+- `gTableScreenSec` — екран Notion
+- `gNetSyncSec` — мережевий синх
+
+Дефолти в `src/config.h`:
+- `kDefaultClockScreenSec`
+- `kDefaultTableScreenSec`
+- `kDefaultNetSyncSec`
+
+## Структура проєкту
+- `src/config.h` — всі константи/налаштування
+- `src/app_state.*` — стан та RTC змінні
+- `src/display.*` — рендеринг дисплея
+- `src/network.*` — Wi‑Fi, NTP, погода, Notion
+- `src/web.*` — веб‑інтерфейс та OTA‑upload через web
+- `src/hardware.*` — ADC/батарея
+- `src/main.cpp` — ініціалізація та головний цикл
+
+## Безпека
+Токен Notion збережений у прошивці у відкритому вигляді. Для продакшна бажано використовувати проксі/сервер або секрети поза прошивкою.
--- a/boards/esp32-s3-zero.json
+++ b/boards/esp32-s3-zero.json
@@ -0,0 +1,54 @@
+{
+  "build": {
+    "arduino": {
+      "ldscript": "esp32s3_out.ld",
+      "partitions": "default.csv"
+    },
+    "core": "esp32",
+    "extra_flags": [
+      "-DARDUINO_ESP32S3_DEV",
+      "-DARDUINO_USB_MODE=1",
+      "-DARDUINO_RUNNING_CORE=1",
+      "-DARDUINO_EVENT_RUNNING_CORE=1"
+    ],
+    "f_cpu": "240000000L",
+    "f_flash": "80000000L",
+    "flash_mode": "qio",
+    "hwids": [
+      [
+        "0x303A",
+        "0x1001"
+      ]
+    ],
+    "mcu": "esp32s3",
+    "variant": "esp32s3"
+  },
+  "connectivity": [
+    "bluetooth",
+    "wifi"
+  ],
+  "debug": {
+    "default_tool": "esp-builtin",
+    "onboard_tools": [
+      "esp-builtin"
+    ],
+    "openocd_target": "esp32s3.cfg"
+  },
+  "frameworks": [
+    "arduino",
+    "espidf"
+  ],
+  "name": "ESP32-S3-Zero (4MB)",
+  "url": "https://www.espressif.com/en/products/socs/esp32-s3",
+  "vendor": "Generic",
+  "hardware": {
+    "flash_size": "4MB"
+  },
+  "upload": {
+    "flash_size": "4MB",
+    "maximum_ram_size": 327680,
+    "maximum_size": 4194304,
+    "require_upload_port": true,
+    "speed": 460800
+  }
+}
--- a/include/README
+++ b/include/README
@@ -0,0 +1,37 @@
+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the convention is to give header files names that end with `.h'.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html
--- a/lib/README
+++ b/lib/README
@@ -0,0 +1,46 @@
+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into the executable file.
+
+The source code of each library should be placed in a separate directory
+("lib/your_library_name/[Code]").
+
+For example, see the structure of the following example libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional. for custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+Example contents of `src/main.c` using Foo and Bar:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+The PlatformIO Library Dependency Finder will find automatically dependent
+libraries by scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html
--- a/platformio.ini
+++ b/platformio.ini
@@ -0,0 +1,14 @@
+[env:esp32-s3-devkitm-1]
+platform = espressif32
+board = esp32-s3-zero
+framework = arduino
+board_build.flash_size = 4MB
+board_build.partitions = default.csv
+lib_deps =
+  ZinggJM/GxEPD2@^1.5.5
+  tzapu/WiFiManager@^2.0.17
+  bblanchon/ArduinoJson@^7.2.0
+  olikraus/U8g2_for_Adafruit_GFX@^1.8.0
+build_flags =
+  -DARDUINO_USB_CDC_ON_BOOT=1
+  -DARDUINO_USB_MODE=1
--- a/src/app_state.cpp
+++ b/src/app_state.cpp
@@ -0,0 +1,13 @@
+#include "app_state.h"
+
+RTC_DATA_ATTR time_t gLastNetSyncEpoch = 0;
+RTC_DATA_ATTR char gWeatherText[64] = "Дніпро --C";
+RTC_DATA_ATTR int gNotionCount = 0;
+RTC_DATA_ATTR char gNotionNames[kNotionMaxItems][kNotionNameLen];
+RTC_DATA_ATTR char gNotionDates[kNotionMaxItems][kNotionDateLen];
+RTC_DATA_ATTR uint32_t gClockScreenSec = kDefaultClockScreenSec;
+RTC_DATA_ATTR uint32_t gTableScreenSec = kDefaultTableScreenSec;
+RTC_DATA_ATTR uint32_t gNetSyncSec = kDefaultNetSyncSec;
+
+uint32_t gLastScreenSwitchMs = 0;
+bool gShowTable = false;
--- a/src/app_state.h
+++ b/src/app_state.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include <Arduino.h>
+#include "config.h"
+
+extern RTC_DATA_ATTR time_t gLastNetSyncEpoch;
+extern RTC_DATA_ATTR char gWeatherText[64];
+extern RTC_DATA_ATTR int gNotionCount;
+extern RTC_DATA_ATTR char gNotionNames[kNotionMaxItems][kNotionNameLen];
+extern RTC_DATA_ATTR char gNotionDates[kNotionMaxItems][kNotionDateLen];
+extern RTC_DATA_ATTR uint32_t gClockScreenSec;
+extern RTC_DATA_ATTR uint32_t gTableScreenSec;
+extern RTC_DATA_ATTR uint32_t gNetSyncSec;
+
+extern uint32_t gLastScreenSwitchMs;
+extern bool gShowTable;
--- a/src/config.h
+++ b/src/config.h
@@ -0,0 +1,48 @@
+#pragma once
+
+#include <Arduino.h>
+#include <stdint.h>
+#include <time.h>
+
+// WeActStudio 2.9" E-Paper wiring
+constexpr int PIN_BUSY = 6;
+constexpr int PIN_RST = 7;
+constexpr int PIN_DC = 8;
+constexpr int PIN_CS = 9;
+constexpr int PIN_SCK = 10;
+constexpr int PIN_MOSI = 11;
+
+constexpr char kPortalSsid[] = "ElinkInformer-Setup";
+constexpr uint32_t kPortalTimeoutSec = 180;
+constexpr int kStatusBarHeight = 22;
+
+constexpr int kBatteryAdcPin = A0;
+constexpr int kBatteryAdcRefMv = 3300;
+constexpr int kBatteryAdcMax = 4095;
+constexpr int kBatteryDividerNum = 2;
+constexpr int kBatteryDividerDen = 1;
+constexpr int kBatteryMvMin = 3200;
+constexpr int kBatteryMvMax = 4200;
+
+constexpr int kWifiConnectAttempts = 5;
+constexpr uint32_t kWifiConnectTimeoutMs = 5000;
+
+constexpr uint32_t kDefaultNetSyncSec = 10 * 60;
+constexpr uint32_t kWakeIntervalSec = 120;
+constexpr uint32_t kDefaultClockScreenSec = 180;
+constexpr uint32_t kDefaultTableScreenSec = 180;
+
+constexpr bool kDeepSleepEnabled = false;
+constexpr bool kWebEnabled = true;
+constexpr char kMdnsHost[] = "tablewatch";
+
+constexpr time_t kMinValidEpoch = 1700000000;
+constexpr char kTimeZone[] = "EET-2EEST,M3.5.0/3,M10.5.0/4";
+constexpr char kWeatherUrl[] =
+  "https://api.open-meteo.com/v1/forecast?latitude=48.45&longitude=34.98&current=temperature_2m,weather_code&timezone=Europe%2FKyiv";
+
+constexpr char kNotionDatabaseId[] = "2eca519844538080a06bc10a2505aa6e";
+constexpr char kNotionToken[] = "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";
+constexpr int kNotionMaxItems = 5;
+constexpr size_t kNotionNameLen = 48;
+constexpr size_t kNotionDateLen = 16;
--- a/src/display.cpp
+++ b/src/display.cpp
@@ -0,0 +1,335 @@
+#include "display.h"
+
+#include <SPI.h>
+#include <GxEPD2_3C.h>
+#include <Fonts/FreeMonoBold9pt7b.h>
+#include <Fonts/FreeMonoBold24pt7b.h>
+#include <U8g2_for_Adafruit_GFX.h>
+
+#include "app_state.h"
+#include "config.h"
+#include "network.h"
+
+GxEPD2_3C<GxEPD2_290_C90c, GxEPD2_290_C90c::HEIGHT> display(
+  GxEPD2_290_C90c(PIN_CS, PIN_DC, PIN_RST, PIN_BUSY)
+);
+U8G2_FOR_ADAFRUIT_GFX u8g2Fonts;
+
+void initDisplay() {
+  SPI.begin(PIN_SCK, -1, PIN_MOSI, PIN_CS);
+  display.init(115200);
+  u8g2Fonts.begin(display);
+}
+
+int utf8CharLen(char c) {
+  uint8_t uc = static_cast<uint8_t>(c);
+  if ((uc & 0x80) == 0) {
+    return 1;
+  }
+  if ((uc & 0xE0) == 0xC0) {
+    return 2;
+  }
+  if ((uc & 0xF0) == 0xE0) {
+    return 3;
+  }
+  if ((uc & 0xF8) == 0xF0) {
+    return 4;
+  }
+  return 1;
+}
+
+void truncateUtf8ToWidth(const char *src, int maxWidth, char *out, size_t outSize) {
+  if (!src || outSize == 0) {
+    return;
+  }
+  out[0] = '\0';
+  size_t outLen = 0;
+  const char *p = src;
+  while (*p && (outLen + 1) < outSize) {
+    int len = utf8CharLen(*p);
+    if (outLen + len >= outSize) {
+      break;
+    }
+    memcpy(out + outLen, p, len);
+    outLen += len;
+    out[outLen] = '\0';
+    if (u8g2Fonts.getUTF8Width(out) > maxWidth) {
+      out[outLen - len] = '\0';
+      outLen -= len;
+      break;
+    }
+    p += len;
+  }
+  if (*p) {
+    const char *ellipsis = "...";
+    if (u8g2Fonts.getUTF8Width(out) + u8g2Fonts.getUTF8Width(ellipsis) <= maxWidth) {
+      strlcat(out, ellipsis, outSize);
+    } else {
+      while (outLen > 0) {
+        size_t newLen = outLen;
+        if (newLen == 0) {
+          break;
+        }
+        do {
+          --newLen;
+        } while (newLen > 0 && (static_cast<uint8_t>(out[newLen]) & 0xC0) == 0x80);
+        outLen = newLen;
+        out[outLen] = '\0';
+        if (u8g2Fonts.getUTF8Width(out) + u8g2Fonts.getUTF8Width(ellipsis) <= maxWidth) {
+          strlcat(out, ellipsis, outSize);
+          break;
+        }
+      }
+    }
+  }
+}
+
+void drawWifiIcon(int16_t x, int16_t y, int level) {
+  const int barW = 3;
+  const int barGap = 2;
+  const int barHeights[4] = {3, 5, 8, 11};
+  const int baseY = y + 11;
+
+  for (int i = 0; i < 4; ++i) {
+    int barH = barHeights[i];
+    int barX = x + i * (barW + barGap);
+    int barY = baseY - barH;
+    if (i < level) {
+      display.fillRect(barX, barY, barW, barH, GxEPD_BLACK);
+    } else {
+      display.drawRect(barX, barY, barW, barH, GxEPD_BLACK);
+    }
+  }
+}
+
+void drawBatteryIcon(int16_t x, int16_t y, int percent) {
+  const int bodyW = 22;
+  const int bodyH = 10;
+  const int capW = 2;
+  const int capH = 4;
+
+  display.drawRect(x, y, bodyW, bodyH, GxEPD_BLACK);
+  display.fillRect(x + bodyW, y + (bodyH - capH) / 2, capW, capH, GxEPD_BLACK);
+
+  int clamped = constrain(percent, 0, 100);
+  int fillW = (bodyW - 2) * clamped / 100;
+  if (fillW > 0) {
+    uint16_t fillColor = clamped <= 20 ? GxEPD_RED : GxEPD_BLACK;
+    display.fillRect(x + 1, y + 1, fillW, bodyH - 2, fillColor);
+  }
+}
+
+void drawPortalIndicator(int16_t x, int16_t y) {
+  display.setFont(nullptr);
+  display.setTextColor(GxEPD_RED);
+  display.setCursor(x, y);
+  display.print("P");
+}
+
+void drawWeather(int16_t width, const char *weatherText) {
+  const int wifiX = 8;
+  const int wifiW = 4 * 3 + 3 * 2;
+  const int batteryX = width - 8 - 22 - 2;
+  const int startX = wifiX + wifiW + 8;
+  const int endX = batteryX - 6;
+  if (endX <= startX || !weatherText || weatherText[0] == '\0') {
+    return;
+  }
+
+  u8g2Fonts.setFontMode(1);
+  u8g2Fonts.setFontDirection(0);
+  u8g2Fonts.setForegroundColor(GxEPD_BLACK);
+  u8g2Fonts.setBackgroundColor(GxEPD_WHITE);
+  u8g2Fonts.setFont(u8g2_font_unifont_t_cyrillic);
+  int16_t textW = u8g2Fonts.getUTF8Width(weatherText);
+  int16_t tx = startX + (endX - startX - textW) / 2;
+  int16_t ty = 16;
+  u8g2Fonts.setCursor(tx, ty);
+  u8g2Fonts.print(weatherText);
+}
+
+void renderStatus(const String &line1, const String &line2, int wifiLevel, int batteryPercent,
+                  bool portalActive, uint16_t line2Color) {
+  display.setRotation(3);
+  display.setTextColor(GxEPD_BLACK);
+  display.setFont(&FreeMonoBold9pt7b);
+
+  display.firstPage();
+  do {
+    display.fillScreen(GxEPD_WHITE);
+    int16_t width = display.width();
+    display.drawRect(2, 2, width - 4, display.height() - 4, GxEPD_BLACK);
+    display.drawFastHLine(2, kStatusBarHeight, width - 4, GxEPD_RED);
+    drawWifiIcon(8, 5, wifiLevel);
+    if (portalActive) {
+      drawPortalIndicator(8 + 4 * (3 + 2) + 4, 14);
+      display.setFont(&FreeMonoBold9pt7b);
+      display.setTextColor(GxEPD_BLACK);
+    }
+    drawBatteryIcon(width - 8 - 22 - 2, 6, batteryPercent);
+    drawWeather(width, gWeatherText);
+
+    display.setCursor(10, kStatusBarHeight + 22);
+    display.print(line1);
+    display.setTextColor(line2Color);
+    display.setCursor(10, kStatusBarHeight + 44);
+    display.print(line2);
+  } while (display.nextPage());
+}
+
+void drawFlipCard(int16_t x, int16_t y, int16_t w, int16_t h, const char *text) {
+  display.drawRect(x, y, w, h, GxEPD_BLACK);
+  int16_t midY = y + h / 2;
+  display.drawFastHLine(x, midY, w, GxEPD_BLACK);
+
+  display.setFont(nullptr);
+  int16_t tbx, tby;
+  uint16_t tbw, tbh;
+  int textSize = 10;
+  for (; textSize > 1; --textSize) {
+    display.setTextSize(textSize);
+    display.getTextBounds(text, 0, 0, &tbx, &tby, &tbw, &tbh);
+    if (tbw <= (w - 8) && tbh <= (h - 8)) {
+      break;
+    }
+  }
+  display.getTextBounds(text, 0, 0, &tbx, &tby, &tbw, &tbh);
+  int16_t tx = x + (w - tbw) / 2 - tbx;
+  int16_t ty = y + (h - tbh) / 2 - tby;
+  display.setCursor(tx, ty);
+  display.setTextColor(GxEPD_BLACK);
+  display.print(text);
+  display.setTextSize(1);
+}
+
+void renderClock(int wifiLevel, int batteryPercent) {
+  struct tm timeinfo;
+  bool timeOk = getLocalTimeSnapshot(&timeinfo);
+
+  char hh[3] = "--";
+  char mm[3] = "--";
+  if (timeOk) {
+    snprintf(hh, sizeof(hh), "%02d", timeinfo.tm_hour);
+    snprintf(mm, sizeof(mm), "%02d", timeinfo.tm_min);
+  }
+
+  display.setRotation(3);
+  display.setFont(&FreeMonoBold9pt7b);
+
+  display.firstPage();
+  do {
+    display.fillScreen(GxEPD_WHITE);
+    int16_t width = display.width();
+    int16_t height = display.height();
+
+    display.drawRect(2, 2, width - 4, height - 4, GxEPD_BLACK);
+    display.drawFastHLine(2, kStatusBarHeight, width - 4, GxEPD_RED);
+    drawWifiIcon(8, 5, wifiLevel);
+    drawBatteryIcon(width - 8 - 22 - 2, 6, batteryPercent);
+    drawWeather(width, gWeatherText);
+
+    int16_t margin = 2;
+    int16_t gap = 6;
+    int16_t topY = kStatusBarHeight + 2;
+    int16_t bottomY = height - 2;
+    int16_t cardH = bottomY - topY;
+    int16_t cardW = (width - 2 * margin - gap) / 2;
+    int16_t leftX = margin;
+    int16_t rightX = leftX + cardW + gap;
+
+    drawFlipCard(leftX, topY, cardW, cardH, hh);
+    drawFlipCard(rightX, topY, cardW, cardH, mm);
+
+    int16_t colonX = leftX + cardW + gap / 2;
+    int16_t colonY = topY + cardH / 2;
+    display.fillCircle(colonX, colonY - 10, 2, GxEPD_RED);
+    display.fillCircle(colonX, colonY + 10, 2, GxEPD_RED);
+  } while (display.nextPage());
+}
+
+void renderTable(int wifiLevel, int batteryPercent) {
+  struct tm timeinfo;
+  bool timeOk = getLocalTimeSnapshot(&timeinfo);
+  char timeText[6] = "--:--";
+  if (timeOk) {
+    snprintf(timeText, sizeof(timeText), "%02d:%02d", timeinfo.tm_hour, timeinfo.tm_min);
+  }
+
+  display.setRotation(3);
+  display.setFont(&FreeMonoBold9pt7b);
+
+  display.firstPage();
+  do {
+    display.fillScreen(GxEPD_WHITE);
+    int16_t width = display.width();
+    int16_t height = display.height();
+
+    display.drawRect(2, 2, width - 4, height - 4, GxEPD_BLACK);
+    display.drawFastHLine(2, kStatusBarHeight, width - 4, GxEPD_RED);
+    const int wifiX = 8;
+    const int wifiW = 4 * 3 + 3 * 2;
+    const int batteryX = width - 8 - 22 - 2;
+    drawWifiIcon(wifiX, 5, wifiLevel);
+    drawBatteryIcon(batteryX, 6, batteryPercent);
+
+    display.setFont(&FreeMonoBold9pt7b);
+    display.setTextColor(GxEPD_BLACK);
+    int16_t tbx, tby;
+    uint16_t tbw, tbh;
+    display.getTextBounds(timeText, 0, 0, &tbx, &tby, &tbw, &tbh);
+    int16_t timeX = wifiX + wifiW + 6;
+    int16_t timeY = 16;
+    display.setCursor(timeX, timeY);
+    display.print(timeText);
+
+    int16_t weatherEndX = batteryX - 6;
+    int16_t timeRightX = timeX + tbw + 6;
+    if (weatherEndX > timeRightX) {
+      int16_t weatherMaxW = weatherEndX - timeRightX;
+      char weatherBuf[64];
+      u8g2Fonts.setFontMode(1);
+      u8g2Fonts.setFontDirection(0);
+      u8g2Fonts.setForegroundColor(GxEPD_BLACK);
+      u8g2Fonts.setBackgroundColor(GxEPD_WHITE);
+      u8g2Fonts.setFont(u8g2_font_unifont_t_cyrillic);
+      truncateUtf8ToWidth(gWeatherText, weatherMaxW, weatherBuf, sizeof(weatherBuf));
+      int16_t weatherW = u8g2Fonts.getUTF8Width(weatherBuf);
+      int16_t weatherX = weatherEndX - weatherW;
+      u8g2Fonts.setCursor(weatherX, timeY);
+      u8g2Fonts.print(weatherBuf);
+    }
+
+    int16_t topY = kStatusBarHeight + 4;
+    int16_t tableH = height - topY - 6;
+    int16_t rowH = tableH / (kNotionMaxItems + 1);
+    int16_t colSplit = width * 2 / 3;
+
+    u8g2Fonts.setFontMode(1);
+    u8g2Fonts.setFontDirection(0);
+    u8g2Fonts.setForegroundColor(GxEPD_BLACK);
+    u8g2Fonts.setBackgroundColor(GxEPD_WHITE);
+    u8g2Fonts.setFont(u8g2_font_unifont_t_cyrillic);
+
+    int16_t headerY = topY + rowH - 2;
+    u8g2Fonts.setCursor(8, headerY);
+    u8g2Fonts.print("Name");
+    u8g2Fonts.setCursor(colSplit, headerY);
+    u8g2Fonts.print("Дата");
+
+    for (int i = 0; i < kNotionMaxItems; ++i) {
+      if (i >= gNotionCount) {
+        break;
+      }
+      int16_t rowTop = topY + rowH * (i + 1);
+      int16_t textY = rowTop + rowH - 4;
+      char nameBuf[kNotionNameLen];
+      char dateBuf[kNotionDateLen];
+      truncateUtf8ToWidth(gNotionNames[i], colSplit - 12, nameBuf, sizeof(nameBuf));
+      truncateUtf8ToWidth(gNotionDates[i], width - colSplit - 8, dateBuf, sizeof(dateBuf));
+      u8g2Fonts.setCursor(8, textY);
+      u8g2Fonts.print(nameBuf);
+      u8g2Fonts.setCursor(colSplit, textY);
+      u8g2Fonts.print(dateBuf);
+    }
+  } while (display.nextPage());
+}
--- a/src/display.h
+++ b/src/display.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include <Arduino.h>
+#include <GxEPD2_3C.h>
+
+void initDisplay();
+void renderStatus(const String &line1, const String &line2, int wifiLevel, int batteryPercent,
+                  bool portalActive = false, uint16_t line2Color = GxEPD_BLACK);
+void renderClock(int wifiLevel, int batteryPercent);
+void renderTable(int wifiLevel, int batteryPercent);
--- a/src/hardware.cpp
+++ b/src/hardware.cpp
@@ -0,0 +1,20 @@
+#include <Arduino.h>
+#include "config.h"
+
+void initAnalog() {
+  analogReadResolution(12);
+  analogSetPinAttenuation(kBatteryAdcPin, ADC_11db);
+}
+
+int readBatteryPercent() {
+  uint16_t raw = analogRead(kBatteryAdcPin);
+  int mv = static_cast<int>(raw) * kBatteryAdcRefMv / kBatteryAdcMax;
+  mv = mv * kBatteryDividerNum / kBatteryDividerDen;
+  if (mv <= kBatteryMvMin) {
+    return 0;
+  }
+  if (mv >= kBatteryMvMax) {
+    return 100;
+  }
+  return (mv - kBatteryMvMin) * 100 / (kBatteryMvMax - kBatteryMvMin);
+}
--- a/src/hardware.h
+++ b/src/hardware.h
@@ -0,0 +1,4 @@
+#pragma once
+
+void initAnalog();
+int readBatteryPercent();
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -0,0 +1,76 @@
+#include <Arduino.h>
+#include <esp_sleep.h>
+
+#include "app_state.h"
+#include "config.h"
+#include "display.h"
+#include "hardware.h"
+#include "network.h"
+#include "web.h"
+
+void setup() {
+  Serial.begin(115200);
+  uint32_t serialWaitStart = millis();
+  while (!Serial && (millis() - serialWaitStart) < 1500) {
+    delay(10);
+  }
+  Serial.println("Boot");
+  delay(200);
+
+  initDisplay();
+  initAnalog();
+
+  int batteryPercent = readBatteryPercent();
+  time_t now = time(nullptr);
+  bool timeValid = now >= kMinValidEpoch;
+  bool needNetSync = !timeValid || gLastNetSyncEpoch == 0 ||
+                     (timeValid && (now - gLastNetSyncEpoch) >= gNetSyncSec);
+  int wifiLevel = 0;
+  if (needNetSync) {
+    performNetSync(batteryPercent, &wifiLevel);
+  }
+
+  gShowTable = false;
+  renderClock(wifiLevel, batteryPercent);
+  gLastScreenSwitchMs = millis();
+  if (kDeepSleepEnabled) {
+    esp_sleep_enable_timer_wakeup(static_cast<uint64_t>(kWakeIntervalSec) * 1000000ULL);
+    esp_deep_sleep_start();
+  }
+}
+
+void loop() {
+  delay(1000);
+  if (kDeepSleepEnabled) {
+    return;
+  }
+  webLoop();
+
+  uint32_t nowMs = millis();
+  uint32_t currentScreenSec = gShowTable ? gTableScreenSec : gClockScreenSec;
+  if ((nowMs - gLastScreenSwitchMs) < (currentScreenSec * 1000UL)) {
+    return;
+  }
+  gLastScreenSwitchMs = nowMs;
+
+  time_t now = time(nullptr);
+  bool timeValid = now >= kMinValidEpoch;
+  bool needNetSync = !timeValid || gLastNetSyncEpoch == 0 ||
+                     (timeValid && (now - gLastNetSyncEpoch) >= gNetSyncSec);
+  int batteryPercent = readBatteryPercent();
+  int wifiLevel = 0;
+  if (needNetSync) {
+    performNetSync(batteryPercent, &wifiLevel);
+  }
+
+  if (gNotionCount <= 0) {
+    gShowTable = false;
+  } else {
+    gShowTable = !gShowTable;
+  }
+  if (gShowTable) {
+    renderTable(wifiLevel, batteryPercent);
+  } else {
+    renderClock(wifiLevel, batteryPercent);
+  }
+}
--- a/src/network.cpp
+++ b/src/network.cpp
@@ -0,0 +1,278 @@
+#include "network.h"
+
+#include <WiFi.h>
+#include <WiFiManager.h>
+#include <WiFiClientSecure.h>
+#include <HTTPClient.h>
+#include <ArduinoJson.h>
+#include <time.h>
+
+#include "app_state.h"
+#include "config.h"
+#include "display.h"
+#include "web.h"
+
+int wifiLevelFromRssi(int32_t rssi) {
+  if (rssi == 0) {
+    return 0;
+  }
+  if (rssi <= -100) {
+    return 0;
+  }
+  if (rssi >= -50) {
+    return 4;
+  }
+  return (rssi + 100) * 4 / 50;
+}
+
+bool syncTime() {
+  configTzTime(kTimeZone, "pool.ntp.org", "time.nist.gov", "time.google.com");
+  struct tm timeinfo;
+  for (int i = 0; i < 10; ++i) {
+    if (getLocalTime(&timeinfo, 1000)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool getLocalTimeSnapshot(struct tm *timeinfo) {
+  time_t now = time(nullptr);
+  if (now < kMinValidEpoch) {
+    return false;
+  }
+  localtime_r(&now, timeinfo);
+  return true;
+}
+
+const char *weatherLabelFromCode(int code) {
+  if (code < 0) {
+    return "хмарно";
+  }
+  if (code == 0) {
+    return "ясно";
+  }
+  if (code == 1 || code == 2) {
+    return "мінливо";
+  }
+  if (code == 3) {
+    return "хмарно";
+  }
+  if (code == 45 || code == 48) {
+    return "туман";
+  }
+  if (code == 95 || code == 96 || code == 99) {
+    return "гроза";
+  }
+  if ((code >= 51 && code <= 57)) {
+    return "мряка";
+  }
+  if ((code >= 61 && code <= 67) || (code >= 80 && code <= 82)) {
+    return "дощ";
+  }
+  if ((code >= 71 && code <= 77) || (code >= 85 && code <= 86)) {
+    return "сніг";
+  }
+  return "хмарно";
+}
+
+bool updateWeather() {
+  if (WiFi.status() != WL_CONNECTED) {
+    return false;
+  }
+
+  WiFiClientSecure client;
+  client.setInsecure();
+  HTTPClient http;
+  if (!http.begin(client, kWeatherUrl)) {
+    return false;
+  }
+  int httpCode = http.GET();
+  if (httpCode != HTTP_CODE_OK) {
+    http.end();
+    return false;
+  }
+
+  String payload = http.getString();
+  http.end();
+
+  StaticJsonDocument<1024> doc;
+  DeserializationError err = deserializeJson(doc, payload);
+  if (err) {
+    return false;
+  }
+
+  float temp = doc["current"]["temperature_2m"] | NAN;
+  int code = doc["current"]["weather_code"] | -1;
+  if (isnan(temp)) {
+    return false;
+  }
+
+  const char *label = weatherLabelFromCode(code);
+  snprintf(gWeatherText, sizeof(gWeatherText), "Дніпро %+.0fC %s", temp, label);
+  return true;
+}
+
+bool updateNotion() {
+  if (WiFi.status() != WL_CONNECTED) {
+    return false;
+  }
+  Serial.println("Notion: запрос");
+  WiFiClientSecure client;
+  client.setInsecure();
+  HTTPClient http;
+  String url = String("https://api.notion.com/v1/databases/") + kNotionDatabaseId + "/query";
+  if (!http.begin(client, url)) {
+    Serial.println("Notion: http begin fail");
+    return false;
+  }
+  http.addHeader("Content-Type", "application/json");
+  http.addHeader("Authorization", String("Bearer ") + kNotionToken);
+  http.addHeader("Notion-Version", "2022-06-28");
+
+  StaticJsonDocument<128> req;
+  req["page_size"] = kNotionMaxItems;
+  String body;
+  serializeJson(req, body);
+
+  int httpCode = http.POST(body);
+  if (httpCode != HTTP_CODE_OK) {
+    Serial.printf("Notion: http %d\n", httpCode);
+    http.end();
+    return false;
+  }
+  String payload = http.getString();
+  http.end();
+  Serial.printf("Notion: payload %u bytes\n", payload.length());
+
+  StaticJsonDocument<8192> doc;
+  DeserializationError err = deserializeJson(doc, payload);
+  if (err) {
+    Serial.println("Notion: json error");
+    return false;
+  }
+
+  JsonArray results = doc["results"].as<JsonArray>();
+  int idx = 0;
+  for (JsonVariant v : results) {
+    if (idx >= kNotionMaxItems) {
+      break;
+    }
+    JsonObject props = v["properties"].as<JsonObject>();
+    const char *name = "";
+    if (!props.isNull()) {
+      JsonVariant nameProp = props["Name"];
+      if (!nameProp.isNull()) {
+        name = nameProp["title"][0]["plain_text"] | "";
+      }
+      if (name[0] == '\0') {
+        for (JsonPair kv : props) {
+          const char *type = kv.value()["type"] | "";
+          if (strcmp(type, "title") == 0) {
+            name = kv.value()["title"][0]["plain_text"] | "";
+            break;
+          }
+        }
+      }
+    }
+
+    const char *dateStart = "";
+    if (!props.isNull()) {
+      JsonVariant dataProp = props["Data"];
+      if (dataProp.isNull()) {
+        dataProp = props["Date"];
+      }
+      if (dataProp.isNull()) {
+        dataProp = props["Дата"];
+      }
+      if (!dataProp.isNull()) {
+        dateStart = dataProp["date"]["start"] | "";
+        if (dateStart[0] == '\0') {
+          dateStart = dataProp["rich_text"][0]["plain_text"] | "";
+        }
+      }
+      if (dateStart[0] == '\0') {
+        for (JsonPair kv : props) {
+          const char *type = kv.value()["type"] | "";
+          if (strcmp(type, "date") == 0) {
+            dateStart = kv.value()["date"]["start"] | "";
+            break;
+          }
+        }
+      }
+    }
+    strlcpy(gNotionNames[idx], name, sizeof(gNotionNames[idx]));
+    if (dateStart && dateStart[0] != '\0') {
+      char dateBuf[kNotionDateLen];
+      strlcpy(dateBuf, dateStart, sizeof(dateBuf));
+      dateBuf[10] = '\0';
+      strlcpy(gNotionDates[idx], dateBuf, sizeof(gNotionDates[idx]));
+    } else {
+      gNotionDates[idx][0] = '\0';
+    }
+    ++idx;
+  }
+  gNotionCount = idx;
+  Serial.printf("Notion: items %d\n", gNotionCount);
+  return true;
+}
+
+bool waitForWifi(uint32_t timeoutMs) {
+  uint32_t startMs = millis();
+  while (WiFi.status() != WL_CONNECTED && (millis() - startMs) < timeoutMs) {
+    delay(200);
+  }
+  return WiFi.status() == WL_CONNECTED;
+}
+
+bool performNetSync(int batteryPercent, int *wifiLevelOut) {
+  int wifiLevel = 0;
+  renderStatus("WiFi", "Connecting...", wifiLevel, batteryPercent);
+  WiFi.mode(WIFI_STA);
+  bool connected = false;
+  static bool webSetup = false;
+  for (int attempt = 0; attempt < kWifiConnectAttempts; ++attempt) {
+    WiFi.begin();
+    if (waitForWifi(kWifiConnectTimeoutMs)) {
+      connected = true;
+      break;
+    }
+  }
+
+  if (!connected) {
+    WiFiManager wm;
+    wm.setConfigPortalTimeout(kPortalTimeoutSec);
+    renderStatus("AP: ElinkInformer-Setup", "Open 192.168.4.1", wifiLevel, batteryPercent, true);
+    connected = wm.autoConnect(kPortalSsid);
+    if (!connected) {
+      renderStatus("WiFi setup failed", "Rebooting...", wifiLevel, batteryPercent, true, GxEPD_RED);
+      delay(3000);
+      ESP.restart();
+    }
+  }
+
+  wifiLevel = wifiLevelFromRssi(WiFi.RSSI());
+  if (kWebEnabled && !webSetup) {
+    startWebServer();
+    webSetup = true;
+  }
+  bool timeOk = syncTime();
+  bool weatherOk = updateWeather();
+  bool notionOk = updateNotion();
+  if (!timeOk) {
+    renderStatus("Time sync failed", "Check WiFi", wifiLevel, batteryPercent, false, GxEPD_RED);
+  }
+  if (timeOk || weatherOk || notionOk) {
+    gLastNetSyncEpoch = time(nullptr);
+  }
+
+  if (!kWebEnabled) {
+    WiFi.disconnect(true);
+    WiFi.mode(WIFI_OFF);
+  }
+
+  if (wifiLevelOut) {
+    *wifiLevelOut = wifiLevel;
+  }
+  return timeOk || weatherOk || notionOk;
+}
--- a/src/network.h
+++ b/src/network.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include <Arduino.h>
+
+int wifiLevelFromRssi(int32_t rssi);
+bool syncTime();
+bool getLocalTimeSnapshot(struct tm *timeinfo);
+bool updateWeather();
+bool updateNotion();
+bool performNetSync(int batteryPercent, int *wifiLevelOut);
--- a/src/web.cpp
+++ b/src/web.cpp
@@ -0,0 +1,169 @@
+#include "web.h"
+
+#include <Arduino.h>
+#include <WiFi.h>
+#include <WebServer.h>
+#include <ESPmDNS.h>
+#include <Update.h>
+#include <time.h>
+
+#include "app_state.h"
+#include "config.h"
+#include "hardware.h"
+
+namespace {
+WebServer gServer(80);
+bool gWebStarted = false;
+
+uint32_t clampIntervalSec(uint32_t value, uint32_t minValue, uint32_t maxValue) {
+  if (value < minValue) {
+    return minValue;
+  }
+  if (value > maxValue) {
+    return maxValue;
+  }
+  return value;
+}
+
+void handleWebRoot() {
+  String html;
+  html.reserve(2400);
+  html += "<!doctype html><html lang=\"uk\"><head>";
+  html += "<meta charset=\"utf-8\"><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">";
+  html += "<link rel=\"stylesheet\" href=\"https://cdn.jsdelivr.net/npm/bootswatch@5.3.2/dist/flatly/bootstrap.min.css\">";
+  html += "<title>TableWatch</title></head><body class=\"bg-light\">";
+  html += "<div class=\"container py-4\"><div class=\"row justify-content-center\"><div class=\"col-lg-6\">";
+  html += "<div class=\"card shadow-sm\"><div class=\"card-body\">";
+  html += "<h4 class=\"card-title mb-3\">TableWatch</h4>";
+  html += "<p class=\"text-muted\">mDNS: <strong>";
+  html += kMdnsHost;
+  html += ".local</strong></p>";
+  html += "<div class=\"mb-3\">";
+  html += "<div><strong>IP:</strong> ";
+  html += WiFi.localIP().toString();
+  html += "</div><div><strong>RSSI:</strong> ";
+  html += String(WiFi.status() == WL_CONNECTED ? WiFi.RSSI() : 0);
+  html += " dBm</div><div><strong>Battery:</strong> ";
+  html += String(readBatteryPercent());
+  html += "%</div><div><strong>Notion:</strong> ";
+  html += String(gNotionCount);
+  html += " items</div><div><strong>Last sync:</strong> ";
+  html += (gLastNetSyncEpoch ? String(ctime(&gLastNetSyncEpoch)) : String("never"));
+  html += "</div>";
+  html += "</div>";
+  html += "<form method=\"POST\" action=\"/save\">";
+  html += "<div class=\"mb-3\"><label class=\"form-label\">Час екрану часу (сек)</label>";
+  html += "<input class=\"form-control\" type=\"number\" min=\"30\" max=\"1800\" name=\"clock\" value=\"";
+  html += gClockScreenSec;
+  html += "\"></div>";
+  html += "<div class=\"mb-3\"><label class=\"form-label\">Час екрану Notion (сек)</label>";
+  html += "<input class=\"form-control\" type=\"number\" min=\"30\" max=\"1800\" name=\"table\" value=\"";
+  html += gTableScreenSec;
+  html += "\"></div>";
+  html += "<div class=\"mb-3\"><label class=\"form-label\">Інтервал синхронізації (сек)</label>";
+  html += "<input class=\"form-control\" type=\"number\" min=\"60\" max=\"3600\" name=\"sync\" value=\"";
+  html += gNetSyncSec;
+  html += "\"></div>";
+  html += "<button class=\"btn btn-primary\" type=\"submit\">Зберегти</button>";
+  html += "</form>";
+  html += "<div class=\"d-flex gap-2 mt-3\">";
+  html += "<a class=\"btn btn-outline-secondary\" href=\"/update\">Оновити прошивку</a>";
+  html += "<a class=\"btn btn-outline-danger\" href=\"/reboot\">Перезавантажити</a>";
+  html += "</div>";
+  html += "</div></div></div></div></div></body></html>";
+  gServer.send(200, "text/html; charset=utf-8", html);
+}
+
+void handleWebSave() {
+  if (!gServer.hasArg("clock") || !gServer.hasArg("table") || !gServer.hasArg("sync")) {
+    gServer.send(400, "text/plain; charset=utf-8", "Missing parameters");
+    return;
+  }
+  uint32_t clockSec = gServer.arg("clock").toInt();
+  uint32_t tableSec = gServer.arg("table").toInt();
+  uint32_t syncSec = gServer.arg("sync").toInt();
+  gClockScreenSec = clampIntervalSec(clockSec, 30, 1800);
+  gTableScreenSec = clampIntervalSec(tableSec, 30, 1800);
+  gNetSyncSec = clampIntervalSec(syncSec, 60, 3600);
+  gServer.sendHeader("Location", "/");
+  gServer.send(303, "text/plain; charset=utf-8", "Saved");
+}
+
+void handleWebUpdatePage() {
+  String html;
+  html.reserve(1200);
+  html += "<!doctype html><html lang=\"uk\"><head>";
+  html += "<meta charset=\"utf-8\"><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">";
+  html += "<link rel=\"stylesheet\" href=\"https://cdn.jsdelivr.net/npm/bootswatch@5.3.2/dist/flatly/bootstrap.min.css\">";
+  html += "<title>Firmware Update</title></head><body class=\"bg-light\">";
+  html += "<div class=\"container py-4\"><div class=\"row justify-content-center\"><div class=\"col-lg-6\">";
+  html += "<div class=\"card shadow-sm\"><div class=\"card-body\">";
+  html += "<h4 class=\"card-title mb-3\">Оновлення прошивки</h4>";
+  html += "<form method=\"POST\" action=\"/update\" enctype=\"multipart/form-data\">";
+  html += "<div class=\"mb-3\"><input class=\"form-control\" type=\"file\" name=\"update\" required></div>";
+  html += "<button class=\"btn btn-primary\" type=\"submit\">Оновити</button>";
+  html += "</form>";
+  html += "<a class=\"btn btn-link mt-3\" href=\"/\">Назад</a>";
+  html += "</div></div></div></div></div></body></html>";
+  gServer.send(200, "text/html; charset=utf-8", html);
+}
+
+void handleWebUpdate() {
+  HTTPUpload &upload = gServer.upload();
+  if (upload.status == UPLOAD_FILE_START) {
+    if (!Update.begin(UPDATE_SIZE_UNKNOWN)) {
+      Update.printError(Serial);
+    }
+  } else if (upload.status == UPLOAD_FILE_WRITE) {
+    if (Update.write(upload.buf, upload.currentSize) != upload.currentSize) {
+      Update.printError(Serial);
+    }
+  } else if (upload.status == UPLOAD_FILE_END) {
+    if (Update.end(true)) {
+      gServer.send(200, "text/plain; charset=utf-8", "OK. Перезавантаження...");
+      delay(500);
+      ESP.restart();
+    } else {
+      Update.printError(Serial);
+      gServer.send(500, "text/plain; charset=utf-8", "Update failed");
+    }
+  } else if (upload.status == UPLOAD_FILE_ABORTED) {
+    Update.end();
+  }
+}
+} // namespace
+
+void startWebServer() {
+  if (gWebStarted) {
+    return;
+  }
+  gServer.on("/", HTTP_GET, handleWebRoot);
+  gServer.on("/save", HTTP_POST, handleWebSave);
+  gServer.on("/update", HTTP_GET, handleWebUpdatePage);
+  gServer.on(
+    "/update",
+    HTTP_POST,
+    []() {},
+    handleWebUpdate
+  );
+  gServer.on("/reboot", HTTP_GET, []() {
+    gServer.send(200, "text/plain; charset=utf-8", "Rebooting...");
+    delay(500);
+    ESP.restart();
+  });
+  gServer.onNotFound([]() {
+    gServer.send(404, "text/plain; charset=utf-8", "Not found");
+  });
+  gServer.begin();
+  if (MDNS.begin(kMdnsHost)) {
+    MDNS.addService("http", "tcp", 80);
+  }
+  gWebStarted = true;
+  Serial.println("Web: started");
+}
+
+void webLoop() {
+  if (kWebEnabled && gWebStarted && WiFi.status() == WL_CONNECTED) {
+    gServer.handleClient();
+  }
+}
--- a/src/web.h
+++ b/src/web.h
@@ -0,0 +1,4 @@
+#pragma once
+
+void startWebServer();
+void webLoop();
--- a/test/README
+++ b/test/README
@@ -0,0 +1,11 @@
+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html