Add CYD SGP30 air quality dashboard with flashable firmware.

LVGL dual-gauge UI for eCO2/TVOC on GPIO22/27, plus archived cyd_28r bins and one-click flash scripts. Co-authored-by: Cursor <cursoragent@cursor.com>
2026-10-18 20:56:46 +08:00
commit 334cdeeb97
16 changed files with 1111 additions and 0 deletions
--- a/.cursor/rules/git-and-docs.mdc
+++ b/.cursor/rules/git-and-docs.mdc
@@ -0,0 +1,14 @@
+---
+description: 每次改动必须提交 Git 并更新文档
+alwaysApply: true
+---
+
+# Git 与文档
+
+对本项目做任何功能、行为或配置改动后，在结束本次任务前必须：
+
+1. **更新文档**：至少更新 `README.md` 的「功能 / 硬件 / 变更记录」中受影响部分；行为变更写进变更记录表。
+2. **提交 Git**：`git add` 相关文件后 `git commit`（按仓库既有 message 风格；中英文均可，说明 why）。
+3. **不要**在未提交的情况下声称任务已完成。
+
+例外：用户明确说「先别提交」或「不要改文档」时，以用户当次指令为准。
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,8 @@
+.pio
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch
+*.pyc
+__pycache__/
+.DS_Store
--- a/README.md
+++ b/README.md
@@ -0,0 +1,83 @@
+# CYD SGP30 空气质量仪表盘
+
+ESP32 Cheap Yellow Display（ESP32-2432S028R）+ SGP30 + LVGL 空气质量仪表盘。
+
+布局与交互参考同目录下的 [temperature](../temperature) 温湿度项目。
+
+## 硬件
+
+| 项目 | 说明 |
+|------|------|
+| 板子 | CYD ESP32-2432S028R（2.8" ILI9341） |
+| 传感器 | SGP30（eCO2 / TVOC） |
+| SDA | **GPIO22** |
+| SCL | **GPIO27** |
+| 供电 | USB 5V；传感器接 **3.3V** |
+
+接线：`VCC→3.3V`，`GND→GND`，`SDA→GPIO22`，`SCL→GPIO27`。
+
+## 功能
+
+- 横屏网格布局：双圆弧仪表（eCO2 ppm / TVOC ppb）+ 底部左空气质量 / 右趋势图（分区不重叠）
+- EMA 平滑、min/max、综合空气质量条与分级（GOOD / FAIR / POOR / BAD）
+- 上电约 15s 预热提示（`WARM`）；圆弧与质量条缓动动画；趋势折线 SHIFT 更新
+- 短按切换背光（4 档，顶部提示）；长按 ≥0.7s 重置 min/max
+- 连续读失败容错（连续失败才报错）
+- 常亮运行（无自动熄屏 / 休眠）
+
+## 构建与烧录
+
+依赖 [PlatformIO](https://platformio.org/)。
+
+```bash
+pio run -e cyd_28r -t upload
+pio device monitor -b 115200
+```
+
+### 预编译固件（随时刷，不必编译）
+
+已归档到 [`firmware/cyd_28r/`](firmware/cyd_28r/)（含 bootloader / partitions / app）：
+
+```powershell
+cd firmware\cyd_28r
+.\flash.ps1
+# 或 .\flash.ps1 -Port COM3
+```
+
+说明见 [`firmware/README.md`](firmware/README.md)。源码更新后重新打包：`.\firmware\export_from_build.ps1`。
+
+### 环境选择
+
+| 环境 | 适用 |
+|------|------|
+| `cyd_28r` | 标准 ILI9341 CYD（默认） |
+| `cyd_28r_inv` | 颜色反相 / 发白 |
+| `cyd_28_st7789` | USB-C 双口 / ST7789 变体 |
+
+## 项目结构
+
+```
+platformio.ini                 # 板级与库依赖
+include/lv_conf.h              # LVGL 配置
+src/main.cpp                   # 仪表盘主程序
+scripts/exclude_lvgl_asm.py    # 排除 ESP32 不兼容的 LVGL ASM
+firmware/                      # 预编译固件（可离线刷写）
+.cursor/rules/                 # Cursor 协作规则
+README.md                      # 本文档
+```
+
+## 变更约定
+
+每次功能或行为改动须：
+
+1. 更新本 README（及必要时的注释）
+2. `git add` + `git commit` 提交
+
+详见 `.cursor/rules/git-and-docs.mdc`。
+
+## 变更记录
+
+| 日期 | 说明 |
+|------|------|
+| 2026-10-18 | 初版：LVGL 空气质量仪表盘 + SGP30（SDA=GPIO22 / SCL=GPIO27），eCO2/TVOC 双表盘、质量条、趋势图、背光与 min/max |
+| 2026-10-18 | 初始化 Git；归档预编译固件到 `firmware/cyd_28r/`，附一键刷写脚本 |
--- a/firmware/README.md
+++ b/firmware/README.md
@@ -0,0 +1,46 @@
+# 预编译固件（可随时刷写）
+
+当前归档目录：[`cyd_28r/`](cyd_28r/)
+
+对应板子：**CYD ESP32-2432S028R**（ILI9341），SGP30 → SDA=GPIO22 / SCL=GPIO27。  
+版本信息见 [`cyd_28r/VERSION.txt`](cyd_28r/VERSION.txt)。
+
+## 直接刷写（无需重新编译）
+
+1. USB 连接板子  
+2. 在本目录执行：
+
+```powershell
+cd firmware\cyd_28r
+.\flash.ps1
+# 或指定端口
+.\flash.ps1 -Port COM3
+```
+
+也可双击 / 运行 `flash.bat`。
+
+依赖其一即可：
+
+- 已安装 PlatformIO（`pio`，自带 esptool）
+- 或 `pip install esptool`
+
+## 手动 esptool
+
+```bash
+esptool.py --chip esp32 --port COM3 --baud 921600 write_flash -z ^
+  --flash_mode dio --flash_freq 40m --flash_size 4MB ^
+  0x1000 bootloader.bin ^
+  0x8000 partitions.bin ^
+  0xe000 boot_app0.bin ^
+  0x10000 firmware.bin
+```
+
+## 从源码重新打包进本目录
+
+在仓库根目录：
+
+```powershell
+.\firmware\export_from_build.ps1
+# 仅复制、不编译：
+.\firmware\export_from_build.ps1 -SkipBuild
+```
--- a/firmware/cyd_28r/VERSION.txt
+++ b/firmware/cyd_28r/VERSION.txt
@@ -0,0 +1,16 @@
+name: CYD SGP30 air quality dashboard (cyd_28r)
+git: 5b1ffb8
+date: 2026-10-18
+board: ESP32-2432S028R (ILI9341)
+sgp30: SDA=GPIO22 SCL=GPIO27
+flash_size: 4MB
+offsets:
+  0x1000  bootloader.bin
+  0x8000  partitions.bin
+  0xe000  boot_app0.bin
+  0x10000 firmware.bin
+sha256:
+  bootloader.bin  3D234A7471F67B013686DABD4DEE7C1FA915C9928463616A94BC9297ACF1ABF8
+  boot_app0.bin   F94C5D786A7A8FAB06AC5D10E33BF37711A6697636DC037559EA19CC410A17F0
+  firmware.bin    4C4C87AE70BA6529F5B6E177564E5934CDFEC15F65E15ABC7D2483B5BECD79C1
+  partitions.bin  0A8B5720E7B77FF11F1462458C3A509DEE79224E5279898F26D6A2E3AE0517B7
--- a/firmware/cyd_28r/boot_app0.bin
+++ b/firmware/cyd_28r/boot_app0.bin
--- a/firmware/cyd_28r/bootloader.bin
+++ b/firmware/cyd_28r/bootloader.bin
--- a/firmware/cyd_28r/firmware.bin
+++ b/firmware/cyd_28r/firmware.bin
--- a/firmware/cyd_28r/flash.bat
+++ b/firmware/cyd_28r/flash.bat
@@ -0,0 +1,5 @@
+@echo off
+setlocal
+cd /d "%~dp0"
+powershell -NoProfile -ExecutionPolicy Bypass -File "%~dp0flash.ps1" %*
+exit /b %ERRORLEVEL%
--- a/firmware/cyd_28r/flash.ps1
+++ b/firmware/cyd_28r/flash.ps1
@@ -0,0 +1,84 @@
+# Flash archived CYD SGP30 firmware (no rebuild needed)
+# Usage:
+#   .\flash.ps1
+#   .\flash.ps1 -Port COM5
+#   .\flash.ps1 -Port COM5 -Baud 460800
+
+param(
+  [string]$Port = "",
+  [int]$Baud = 921600
+)
+
+$ErrorActionPreference = "Stop"
+$here = Split-Path -Parent $MyInvocation.MyCommand.Path
+Set-Location $here
+
+function Find-Esptool {
+  $pio = Get-Command pio -ErrorAction SilentlyContinue
+  if ($pio) {
+    $pkg = Join-Path $env:USERPROFILE ".platformio\packages\tool-esptoolpy\esptool.py"
+    if (Test-Path $pkg) { return @{ Kind = "py"; Path = $pkg } }
+  }
+  $py = Get-Command python -ErrorAction SilentlyContinue
+  if ($py) {
+    try {
+      & python -c "import esptool" 2>$null
+      if ($LASTEXITCODE -eq 0) { return @{ Kind = "mod"; Path = "esptool" } }
+    } catch {}
+  }
+  $esp = Get-Command esptool.py -ErrorAction SilentlyContinue
+  if ($esp) { return @{ Kind = "py"; Path = $esp.Source } }
+  return $null
+}
+
+if (-not $Port) {
+  $ports = @()
+  try {
+    Add-Type -AssemblyName System.IO.Ports -ErrorAction SilentlyContinue | Out-Null
+    $ports = [System.IO.Ports.SerialPort]::GetPortNames() | Sort-Object
+  } catch {}
+  if (-not $ports -or $ports.Count -eq 0) {
+    $ports = Get-CimInstance Win32_SerialPort -ErrorAction SilentlyContinue |
+      Select-Object -ExpandProperty DeviceID | Sort-Object
+  }
+  if (-not $ports -or $ports.Count -eq 0) {
+    Write-Error "No serial ports found. Plug in the CYD USB cable, then retry with -Port COMx"
+  }
+  if ($ports.Count -eq 1) {
+    $Port = $ports[0]
+  } else {
+    Write-Host "Available ports: $($ports -join ', ')"
+    $Port = $ports[-1]
+    Write-Host "Using last port: $Port (override with -Port)"
+  }
+}
+
+$tool = Find-Esptool
+if (-not $tool) {
+  Write-Error "esptool not found. Install PlatformIO (`pio`) or: pip install esptool"
+}
+
+$argsCommon = @(
+  "--chip", "esp32",
+  "--port", $Port,
+  "--baud", "$Baud",
+  "--before", "default_reset",
+  "--after", "hard_reset",
+  "write_flash", "-z",
+  "--flash_mode", "dio",
+  "--flash_freq", "40m",
+  "--flash_size", "4MB",
+  "0x1000", "bootloader.bin",
+  "0x8000", "partitions.bin",
+  "0xe000", "boot_app0.bin",
+  "0x10000", "firmware.bin"
+)
+
+Write-Host "Flashing $here -> $Port @ $Baud"
+if ($tool.Kind -eq "mod") {
+  & python -m esptool @argsCommon
+} else {
+  & python $tool.Path @argsCommon
+}
+if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+Write-Host "Done. Open serial monitor at 115200 if needed."
--- a/firmware/cyd_28r/partitions.bin
+++ b/firmware/cyd_28r/partitions.bin
--- a/firmware/export_from_build.ps1
+++ b/firmware/export_from_build.ps1
@@ -0,0 +1,57 @@
+# Rebuild (optional) and refresh firmware/cyd_28r from PlatformIO build output.
+# Usage:
+#   .\firmware\export_from_build.ps1
+#   .\firmware\export_from_build.ps1 -SkipBuild
+
+param([switch]$SkipBuild)
+
+$ErrorActionPreference = "Stop"
+$root = Split-Path -Parent (Split-Path -Parent $MyInvocation.MyCommand.Path)
+Set-Location $root
+
+if (-not $SkipBuild) {
+  pio run -e cyd_28r
+  if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+}
+
+$src = Join-Path $root ".pio\build\cyd_28r"
+$dst = Join-Path $root "firmware\cyd_28r"
+New-Item -ItemType Directory -Force -Path $dst | Out-Null
+
+Copy-Item (Join-Path $src "bootloader.bin") $dst -Force
+Copy-Item (Join-Path $src "partitions.bin") $dst -Force
+Copy-Item (Join-Path $src "firmware.bin") $dst -Force
+
+$bootApp = Join-Path $env:USERPROFILE ".platformio\packages\framework-arduinoespressif32\tools\partitions\boot_app0.bin"
+if (-not (Test-Path $bootApp)) {
+  Write-Error "boot_app0.bin not found under PlatformIO packages"
+}
+Copy-Item $bootApp (Join-Path $dst "boot_app0.bin") -Force
+
+$git = "nogit"
+try {
+  $git = (git -C $root rev-parse --short HEAD 2>$null).Trim()
+  if (-not $git) { $git = "nogit" }
+} catch { $git = "nogit" }
+
+$date = Get-Date -Format "yyyy-MM-dd"
+$hashes = Get-FileHash (Join-Path $dst "*.bin") -Algorithm SHA256
+$lines = @(
+  "name: CYD SGP30 air quality dashboard (cyd_28r)",
+  "git: $git",
+  "date: $date",
+  "board: ESP32-2432S028R (ILI9341)",
+  "sgp30: SDA=GPIO22 SCL=GPIO27",
+  "flash_size: 4MB",
+  "offsets:",
+  "  0x1000  bootloader.bin",
+  "  0x8000  partitions.bin",
+  "  0xe000  boot_app0.bin",
+  "  0x10000 firmware.bin",
+  "sha256:"
+)
+foreach ($h in $hashes) {
+  $lines += ("  {0,-15} {1}" -f (Split-Path $h.Path -Leaf), $h.Hash)
+}
+$lines | Set-Content -Encoding utf8 (Join-Path $dst "VERSION.txt")
+Write-Host "Exported -> $dst (git $git)"
--- a/include/lv_conf.h
+++ b/include/lv_conf.h
@@ -0,0 +1,86 @@
+#ifndef LV_CONF_H
+#define LV_CONF_H
+
+#include <stdint.h>
+
+#define LV_COLOR_DEPTH 16
+
+#define LV_MEM_SIZE (48 * 1024U)
+#define LV_DEF_REFR_PERIOD 16
+#define LV_DPI_DEF 130
+
+/* ESP32 无 Helium，关掉以免 .S 汇编被错误预处理 */
+#define LV_USE_DRAW_SW_ASM LV_DRAW_SW_ASM_NONE
+
+#define LV_USE_OS LV_OS_NONE
+#define LV_USE_STDLIB_MALLOC LV_STDLIB_BUILTIN
+#define LV_USE_STDLIB_STRING LV_STDLIB_BUILTIN
+#define LV_USE_STDLIB_SPRINTF LV_STDLIB_BUILTIN
+
+#define LV_USE_LOG 0
+#define LV_USE_ASSERT_NULL 1
+#define LV_USE_ASSERT_MALLOC 1
+
+#define LV_FONT_MONTSERRAT_12 1
+#define LV_FONT_MONTSERRAT_14 1
+#define LV_FONT_MONTSERRAT_16 1
+#define LV_FONT_MONTSERRAT_20 1
+#define LV_FONT_MONTSERRAT_24 1
+#define LV_FONT_MONTSERRAT_28 1
+#define LV_FONT_MONTSERRAT_32 1
+#define LV_FONT_MONTSERRAT_40 1
+#define LV_FONT_DEFAULT &lv_font_montserrat_14
+
+#define LV_USE_FLOAT 1
+#define LV_USE_MATRIX 0
+
+#define LV_USE_LABEL 1
+#define LV_LABEL_TEXT_SELECTION 0
+#define LV_LABEL_LONG_TXT_HINT 1
+
+#define LV_USE_ARC 1
+#define LV_USE_BAR 1
+#define LV_USE_BTN 1
+#define LV_USE_BUTTON 1
+#define LV_USE_IMG 1
+#define LV_USE_IMAGE 1
+#define LV_USE_LINE 1
+#define LV_USE_SLIDER 1
+#define LV_USE_SWITCH 1
+#define LV_USE_TEXTAREA 0
+#define LV_USE_CHECKBOX 0
+#define LV_USE_DROPDOWN 0
+#define LV_USE_ROLLER 0
+#define LV_USE_TABLE 0
+#define LV_USE_CALENDAR 0
+#define LV_USE_CHART 1
+#define LV_USE_KEYBOARD 0
+#define LV_USE_LIST 0
+#define LV_USE_MENU 0
+#define LV_USE_MSGBOX 0
+#define LV_USE_SPAN 0
+#define LV_USE_SPINBOX 0
+#define LV_USE_SPINNER 1
+#define LV_USE_TABVIEW 0
+#define LV_USE_TILEVIEW 0
+#define LV_USE_WIN 0
+#define LV_USE_LED 1
+#define LV_USE_SCALE 1
+
+#define LV_USE_THEME_DEFAULT 1
+#define LV_THEME_DEFAULT_DARK 1
+#define LV_THEME_DEFAULT_GROW 0
+#define LV_THEME_DEFAULT_TRANSITION_TIME 80
+
+#define LV_USE_FLEX 1
+#define LV_USE_GRID 1
+
+#define LV_USE_TFT_ESPI 1
+
+#define LV_USE_OBSERVER 0
+#define LV_USE_SYSMON 0
+#define LV_USE_PROFILER 0
+#define LV_USE_DEMO_WIDGETS 0
+#define LV_USE_DEMO_BENCHMARK 0
+
+#endif /* LV_CONF_H */
--- a/platformio.ini
+++ b/platformio.ini
@@ -0,0 +1,68 @@
+; CYD ESP32-2432S028R — LVGL SGP30 空气质量仪表盘
+; SGP30 SDA -> GPIO22, SCL -> GPIO27
+
+[platformio]
+default_envs = cyd_28r
+
+[env]
+platform = espressif32@6.9.0
+board = esp32dev
+framework = arduino
+monitor_speed = 115200
+upload_speed = 921600
+board_build.partitions = min_spiffs.csv
+lib_deps =
+  lvgl/lvgl@9.2.2
+  bodmer/TFT_eSPI@2.5.43
+  https://github.com/PaulStoffregen/XPT2046_Touchscreen.git
+  adafruit/Adafruit SGP30 Sensor@^2.0.3
+  adafruit/Adafruit BusIO@^1.16.1
+extra_scripts = pre:scripts/exclude_lvgl_asm.py
+build_flags =
+  -D CORE_DEBUG_LEVEL=0
+  -D USER_SETUP_LOADED=1
+  -D USE_HSPI_PORT=1
+  -D ILI9341_2_DRIVER=1
+  -D TFT_WIDTH=240
+  -D TFT_HEIGHT=320
+  -D TFT_MISO=12
+  -D TFT_MOSI=13
+  -D TFT_SCLK=14
+  -D TFT_CS=15
+  -D TFT_DC=2
+  -D TFT_RST=-1
+  -D TFT_BL=21
+  -D TFT_BACKLIGHT_ON=HIGH
+  -D SPI_FREQUENCY=40000000
+  -D SPI_READ_FREQUENCY=20000000
+  -D LOAD_GLCD=1
+  -D LOAD_FONT2=0
+  -D LOAD_FONT4=0
+  -D LOAD_FONT6=0
+  -D LOAD_FONT7=0
+  -D LOAD_FONT8=0
+  -D LOAD_GFXFF=0
+  -D SMOOTH_FONT=0
+  -D TOUCH_CS=-1
+  -D LV_CONF_INCLUDE_SIMPLE=1
+  -I include
+
+; 标准 CYD 2.8" 电阻屏 (ILI9341)
+[env:cyd_28r]
+build_flags =
+  ${env.build_flags}
+
+; 颜色反相版本（若画面色偏/发白可改用此环境）
+[env:cyd_28r_inv]
+build_flags =
+  ${env.build_flags}
+  -D TFT_INVERSION_ON=1
+
+; USB-C 双口 / 7789 变体
+[env:cyd_28_st7789]
+build_flags =
+  ${env.build_flags}
+  -U ILI9341_2_DRIVER
+  -D ST7789_DRIVER=1
+  -D TFT_RGB_ORDER=TFT_BGR
+  -D TFT_INVERSION_ON=1
--- a/scripts/exclude_lvgl_asm.py
+++ b/scripts/exclude_lvgl_asm.py
@@ -0,0 +1,13 @@
+"""Exclude LVGL Helium/Neon .S files that break ESP32 (xtensa) builds."""
+import shutil
+from pathlib import Path
+
+Import("env")  # type: ignore  # noqa: F821
+
+LIBDEPS = Path(env["PROJECT_LIBDEPS_DIR"]) / env["PIOENV"] / "lvgl"  # type: ignore  # noqa: F821
+
+for sub in ("draw/sw/blend/helium", "draw/sw/blend/neon"):
+    target = LIBDEPS / "src" / sub
+    if target.exists():
+        shutil.rmtree(target, ignore_errors=True)
+        print(f"Removed LVGL ASM path: {target}")
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -0,0 +1,631 @@
+/**
+ * CYD ESP32-2432S028R — LVGL SGP30 空气质量仪表盘
+ * SGP30 SDA -> GPIO22, SCL -> GPIO27
+ */
+
+#include <Arduino.h>
+#include <Wire.h>
+#include <lvgl.h>
+#include <TFT_eSPI.h>
+#include <XPT2046_Touchscreen.h>
+#include <Adafruit_SGP30.h>
+#include <math.h>
+
+#define I2C_SDA 22
+#define I2C_SCL 27
+#define TFT_BL_PIN 21
+
+#define XPT2046_IRQ 36
+#define XPT2046_MOSI 32
+#define XPT2046_MISO 39
+#define XPT2046_CLK 25
+#define XPT2046_CS 33
+
+#define SCREEN_WIDTH 320
+#define SCREEN_HEIGHT 240
+#define SGP_READ_MS 1000
+#define SGP_FAIL_TOLERANCE 3
+#define EMA_ALPHA 0.35f
+#define HISTORY_LEN 48
+#define WARMUP_SEC 15
+#define DRAW_BUF_SIZE (SCREEN_WIDTH * SCREEN_HEIGHT / 10 * (LV_COLOR_DEPTH / 8))
+
+/* Gauge display clamps (arc range) */
+#define ECO2_ARC_MAX 2000
+#define TVOC_ARC_MAX 1000
+
+/* Layout grid — every region has exclusive space, no overlaps */
+#define UI_M 6
+#define UI_G 6
+#define UI_HDR_H 22
+#define UI_GAUGE_H 124
+#define UI_GAUGE_W 151
+#define UI_ARC 90
+#define UI_BOT_Y (UI_HDR_H + UI_G + UI_GAUGE_H + UI_G) /* 158 */
+#define UI_BOT_H (SCREEN_HEIGHT - UI_BOT_Y - UI_M)      /* 76 */
+#define UI_BOT_W (SCREEN_WIDTH - 2 * UI_M)              /* 308 */
+#define UI_INFO_W 124
+#define UI_CHART_W (UI_BOT_W - 12 - UI_INFO_W - UI_G)   /* ~160 */
+
+static const lv_color_t COL_BG = lv_color_hex(0x0A1018);
+static const lv_color_t COL_PANEL = lv_color_hex(0x121C2A);
+static const lv_color_t COL_EDGE = lv_color_hex(0x1E2C40);
+static const lv_color_t COL_TEXT = lv_color_hex(0xF2F5FA);
+static const lv_color_t COL_MUTED = lv_color_hex(0x7E90A8);
+static const lv_color_t COL_ECO2 = lv_color_hex(0x4DA3FF);
+static const lv_color_t COL_TVOC = lv_color_hex(0xB07CFF);
+static const lv_color_t COL_OK = lv_color_hex(0x4CAF7A);
+static const lv_color_t COL_WARN = lv_color_hex(0xE6B84D);
+static const lv_color_t COL_BAD = lv_color_hex(0xE05A5A);
+static const lv_color_t COL_ARC_BG = lv_color_hex(0x243247);
+static const lv_color_t COL_CHART_BG = lv_color_hex(0x0E1622);
+
+SPIClass touchscreenSPI = SPIClass(VSPI);
+XPT2046_Touchscreen touchscreen(XPT2046_CS, XPT2046_IRQ);
+Adafruit_SGP30 sgp;
+
+static uint32_t draw_buf[DRAW_BUF_SIZE / 4];
+
+static lv_obj_t *arc_eco2;
+static lv_obj_t *arc_tvoc;
+static lv_obj_t *lbl_eco2_val;
+static lv_obj_t *lbl_tvoc_val;
+static lv_obj_t *lbl_eco2_range;
+static lv_obj_t *lbl_tvoc_range;
+static lv_obj_t *lbl_aqi;
+static lv_obj_t *lbl_eco2_lvl;
+static lv_obj_t *lbl_tvoc_lvl;
+static lv_obj_t *lbl_status;
+static lv_obj_t *lbl_uptime;
+static lv_obj_t *lbl_hint;
+static lv_obj_t *led_status;
+static lv_obj_t *bar_aqi;
+static lv_obj_t *chart;
+static lv_chart_series_t *ser_eco2;
+static lv_chart_series_t *ser_tvoc;
+
+static float disp_eco2 = NAN;
+static float disp_tvoc = NAN;
+static float min_eco2 = NAN;
+static float max_eco2 = NAN;
+static float min_tvoc = NAN;
+static float max_tvoc = NAN;
+static uint32_t last_sgp_ms = 0;
+static uint32_t last_ok_ms = 0;
+static uint32_t boot_ms = 0;
+static uint8_t fail_streak = 0;
+static bool sensor_ok = false;
+static bool iaq_ready = false;
+static uint8_t bright_level = 2;
+static const uint8_t BRIGHT_PWM[4] = {40, 90, 160, 255};
+static uint32_t hint_until_ms = 0;
+
+static void set_backlight(uint8_t level) {
+  bright_level = level & 0x03;
+  ledcWrite(0, BRIGHT_PWM[bright_level]);
+}
+
+static float ema(float prev, float sample) {
+  if (isnan(prev)) return sample;
+  return prev + EMA_ALPHA * (sample - prev);
+}
+
+/* eCO2 color bands (ppm) */
+static lv_color_t eco2_color(float ppm) {
+  if (isnan(ppm)) return COL_MUTED;
+  if (ppm < 800.0f) return COL_OK;
+  if (ppm < 1200.0f) return COL_WARN;
+  return COL_BAD;
+}
+
+/* TVOC color bands (ppb) */
+static lv_color_t tvoc_color(float ppb) {
+  if (isnan(ppb)) return COL_MUTED;
+  if (ppb < 220.0f) return COL_OK;
+  if (ppb < 660.0f) return COL_WARN;
+  return COL_BAD;
+}
+
+static const char *eco2_level_text(float ppm) {
+  if (isnan(ppm)) return "eCO2 --";
+  if (ppm < 800.0f) return "eCO2 Good";
+  if (ppm < 1200.0f) return "eCO2 Fair";
+  if (ppm < 2000.0f) return "eCO2 Poor";
+  return "eCO2 Bad";
+}
+
+static const char *tvoc_level_text(float ppb) {
+  if (isnan(ppb)) return "TVOC --";
+  if (ppb < 220.0f) return "TVOC Good";
+  if (ppb < 660.0f) return "TVOC Fair";
+  if (ppb < 2200.0f) return "TVOC Poor";
+  return "TVOC Bad";
+}
+
+static const char *aqi_text(float eco2, float tvoc) {
+  if (isnan(eco2) || isnan(tvoc)) return "NO DATA";
+  if (eco2 < 800.0f && tvoc < 220.0f) return "GOOD";
+  if (eco2 < 1200.0f && tvoc < 660.0f) return "FAIR";
+  if (eco2 < 2000.0f && tvoc < 2200.0f) return "POOR";
+  return "BAD";
+}
+
+static lv_color_t aqi_color(float eco2, float tvoc) {
+  if (isnan(eco2) || isnan(tvoc)) return COL_BAD;
+  if (eco2 < 800.0f && tvoc < 220.0f) return COL_OK;
+  if (eco2 < 1200.0f && tvoc < 660.0f) return COL_WARN;
+  return COL_BAD;
+}
+
+/* 0..100 score: higher = better air */
+static int aqi_score(float eco2, float tvoc) {
+  if (isnan(eco2) || isnan(tvoc)) return 0;
+  float e_score = 100.0f - (eco2 - 400.0f) * 0.06f; /* 400→100, ~2067→0 */
+  float t_score = 100.0f - tvoc * 0.12f;             /* 0→100, ~833→0 */
+  int score = (int)lroundf((constrain(e_score, 0.0f, 100.0f) +
+                            constrain(t_score, 0.0f, 100.0f)) *
+                           0.5f);
+  return constrain(score, 0, 100);
+}
+
+static void show_hint(const char *text, uint32_t ms) {
+  lv_label_set_text(lbl_hint, text);
+  lv_obj_remove_flag(lbl_hint, LV_OBJ_FLAG_HIDDEN);
+  lv_obj_move_foreground(lbl_hint);
+  hint_until_ms = millis() + ms;
+}
+
+static void reset_minmax(void) {
+  if (!isnan(disp_eco2)) {
+    min_eco2 = max_eco2 = disp_eco2;
+  } else {
+    min_eco2 = max_eco2 = NAN;
+  }
+  if (!isnan(disp_tvoc)) {
+    min_tvoc = max_tvoc = disp_tvoc;
+  } else {
+    min_tvoc = max_tvoc = NAN;
+  }
+  show_hint("min/max reset", 1200);
+}
+
+static void touchscreen_read(lv_indev_t *indev, lv_indev_data_t *data) {
+  LV_UNUSED(indev);
+  static bool was_pressed = false;
+  static uint32_t press_ms = 0;
+
+  if (touchscreen.tirqTouched() && touchscreen.touched()) {
+    TS_Point p = touchscreen.getPoint();
+    data->point.x = map(p.y, 240, 3800, 1, SCREEN_WIDTH);
+    data->point.y = map(p.x, 200, 3700, SCREEN_HEIGHT, 1);
+    data->state = LV_INDEV_STATE_PRESSED;
+    if (!was_pressed) {
+      was_pressed = true;
+      press_ms = millis();
+    }
+  } else {
+    data->state = LV_INDEV_STATE_RELEASED;
+    if (was_pressed) {
+      was_pressed = false;
+      uint32_t held = millis() - press_ms;
+      if (held >= 700) {
+        reset_minmax();
+      } else if (held < 400) {
+        set_backlight((bright_level + 1) & 0x03);
+        char buf[20];
+        lv_snprintf(buf, sizeof(buf), "brightness %u/3", (unsigned)bright_level);
+        show_hint(buf, 900);
+      }
+    }
+  }
+}
+
+static void arc_anim_exec(void *obj, int32_t v) {
+  lv_arc_set_value((lv_obj_t *)obj, v);
+}
+
+static void anim_arc(lv_obj_t *arc, int32_t value) {
+  int32_t cur = lv_arc_get_value(arc);
+  if (cur == value) return;
+  lv_anim_t a;
+  lv_anim_init(&a);
+  lv_anim_set_var(&a, arc);
+  lv_anim_set_values(&a, cur, value);
+  lv_anim_set_duration(&a, 520);
+  lv_anim_set_exec_cb(&a, arc_anim_exec);
+  lv_anim_set_path_cb(&a, lv_anim_path_ease_out);
+  lv_anim_start(&a);
+}
+
+static void bar_anim_exec(void *obj, int32_t v) {
+  lv_bar_set_value((lv_obj_t *)obj, v, LV_ANIM_OFF);
+}
+
+static void anim_bar(lv_obj_t *bar, int32_t value) {
+  int32_t cur = lv_bar_get_value(bar);
+  if (cur == value) return;
+  lv_anim_t a;
+  lv_anim_init(&a);
+  lv_anim_set_var(&a, bar);
+  lv_anim_set_values(&a, cur, value);
+  lv_anim_set_duration(&a, 400);
+  lv_anim_set_exec_cb(&a, bar_anim_exec);
+  lv_anim_set_path_cb(&a, lv_anim_path_ease_out);
+  lv_anim_start(&a);
+}
+
+static lv_obj_t *make_panel(lv_obj_t *parent, int x, int y, int w, int h) {
+  lv_obj_t *p = lv_obj_create(parent);
+  lv_obj_set_pos(p, x, y);
+  lv_obj_set_size(p, w, h);
+  lv_obj_set_style_bg_color(p, COL_PANEL, 0);
+  lv_obj_set_style_bg_opa(p, LV_OPA_COVER, 0);
+  lv_obj_set_style_border_color(p, COL_EDGE, 0);
+  lv_obj_set_style_border_width(p, 1, 0);
+  lv_obj_set_style_radius(p, 12, 0);
+  lv_obj_set_style_pad_all(p, 6, 0);
+  lv_obj_set_style_pad_row(p, 0, 0);
+  lv_obj_set_style_pad_column(p, 0, 0);
+  lv_obj_clear_flag(p, LV_OBJ_FLAG_SCROLLABLE);
+  lv_obj_remove_flag(p, LV_OBJ_FLAG_SCROLLABLE);
+  return p;
+}
+
+static lv_obj_t *make_gauge(lv_obj_t *parent, lv_color_t accent, int max_val) {
+  lv_obj_t *arc = lv_arc_create(parent);
+  lv_obj_set_size(arc, UI_ARC, UI_ARC);
+  lv_obj_align(arc, LV_ALIGN_TOP_MID, 0, 2);
+  lv_arc_set_rotation(arc, 135);
+  lv_arc_set_bg_angles(arc, 0, 270);
+  lv_arc_set_range(arc, 0, max_val);
+  lv_arc_set_value(arc, 0);
+  lv_obj_remove_style(arc, NULL, LV_PART_KNOB);
+  lv_obj_clear_flag(arc, LV_OBJ_FLAG_CLICKABLE);
+  lv_obj_set_style_arc_color(arc, COL_ARC_BG, LV_PART_MAIN);
+  lv_obj_set_style_arc_width(arc, 10, LV_PART_MAIN);
+  lv_obj_set_style_arc_color(arc, accent, LV_PART_INDICATOR);
+  lv_obj_set_style_arc_width(arc, 10, LV_PART_INDICATOR);
+  lv_obj_set_style_arc_rounded(arc, true, LV_PART_MAIN);
+  lv_obj_set_style_arc_rounded(arc, true, LV_PART_INDICATOR);
+  return arc;
+}
+
+static void create_ui(void) {
+  lv_obj_t *scr = lv_screen_active();
+  lv_obj_set_style_bg_color(scr, COL_BG, 0);
+  lv_obj_set_style_bg_opa(scr, LV_OPA_COVER, 0);
+  lv_obj_clear_flag(scr, LV_OBJ_FLAG_SCROLLABLE);
+
+  lv_obj_t *title = lv_label_create(scr);
+  lv_label_set_text(title, "AIR");
+  lv_obj_set_style_text_font(title, &lv_font_montserrat_14, 0);
+  lv_obj_set_style_text_color(title, COL_TEXT, 0);
+  lv_obj_set_pos(title, UI_M, 4);
+
+  lbl_uptime = lv_label_create(scr);
+  lv_label_set_text(lbl_uptime, "up 00:00");
+  lv_obj_set_style_text_font(lbl_uptime, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(lbl_uptime, COL_MUTED, 0);
+  lv_obj_align_to(lbl_uptime, title, LV_ALIGN_OUT_RIGHT_MID, 8, 1);
+
+  led_status = lv_led_create(scr);
+  lv_obj_set_size(led_status, 9, 9);
+  lv_obj_align(led_status, LV_ALIGN_TOP_RIGHT, -UI_M, 6);
+  lv_led_set_color(led_status, COL_WARN);
+  lv_led_on(led_status);
+
+  lbl_status = lv_label_create(scr);
+  lv_label_set_text(lbl_status, "INIT");
+  lv_obj_set_style_text_font(lbl_status, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(lbl_status, COL_MUTED, 0);
+  lv_obj_align(lbl_status, LV_ALIGN_TOP_RIGHT, -(UI_M + 16), 4);
+
+  lbl_hint = lv_label_create(scr);
+  lv_label_set_text(lbl_hint, "");
+  lv_obj_set_style_text_font(lbl_hint, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(lbl_hint, COL_WARN, 0);
+  lv_obj_set_style_bg_color(lbl_hint, COL_BG, 0);
+  lv_obj_set_style_bg_opa(lbl_hint, LV_OPA_COVER, 0);
+  lv_obj_set_style_pad_hor(lbl_hint, 6, 0);
+  lv_obj_align(lbl_hint, LV_ALIGN_TOP_MID, 0, 4);
+  lv_obj_add_flag(lbl_hint, LV_OBJ_FLAG_HIDDEN);
+
+  const int gy = UI_HDR_H + UI_G;
+
+  lv_obj_t *p_eco2 = make_panel(scr, UI_M, gy, UI_GAUGE_W, UI_GAUGE_H);
+  lv_obj_t *e_cap = lv_label_create(p_eco2);
+  lv_label_set_text(e_cap, "eCO2");
+  lv_obj_set_style_text_font(e_cap, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(e_cap, COL_MUTED, 0);
+  lv_obj_align(e_cap, LV_ALIGN_TOP_LEFT, 0, -2);
+
+  arc_eco2 = make_gauge(p_eco2, COL_ECO2, ECO2_ARC_MAX);
+  lbl_eco2_val = lv_label_create(p_eco2);
+  lv_label_set_text(lbl_eco2_val, "----");
+  lv_obj_set_style_text_font(lbl_eco2_val, &lv_font_montserrat_24, 0);
+  lv_obj_set_style_text_color(lbl_eco2_val, COL_ECO2, 0);
+  lv_obj_align(lbl_eco2_val, LV_ALIGN_TOP_MID, 0, 32);
+
+  lv_obj_t *e_unit = lv_label_create(p_eco2);
+  lv_label_set_text(e_unit, "ppm");
+  lv_obj_set_style_text_font(e_unit, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(e_unit, COL_MUTED, 0);
+  lv_obj_align(e_unit, LV_ALIGN_TOP_MID, 0, 58);
+
+  lbl_eco2_range = lv_label_create(p_eco2);
+  lv_label_set_text(lbl_eco2_range, "-- / --");
+  lv_obj_set_style_text_font(lbl_eco2_range, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(lbl_eco2_range, COL_MUTED, 0);
+  lv_obj_align(lbl_eco2_range, LV_ALIGN_BOTTOM_MID, 0, 2);
+
+  lv_obj_t *p_tvoc = make_panel(scr, UI_M + UI_GAUGE_W + UI_G, gy, UI_GAUGE_W, UI_GAUGE_H);
+  lv_obj_t *t_cap = lv_label_create(p_tvoc);
+  lv_label_set_text(t_cap, "TVOC");
+  lv_obj_set_style_text_font(t_cap, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(t_cap, COL_MUTED, 0);
+  lv_obj_align(t_cap, LV_ALIGN_TOP_LEFT, 0, -2);
+
+  arc_tvoc = make_gauge(p_tvoc, COL_TVOC, TVOC_ARC_MAX);
+  lbl_tvoc_val = lv_label_create(p_tvoc);
+  lv_label_set_text(lbl_tvoc_val, "----");
+  lv_obj_set_style_text_font(lbl_tvoc_val, &lv_font_montserrat_24, 0);
+  lv_obj_set_style_text_color(lbl_tvoc_val, COL_TVOC, 0);
+  lv_obj_align(lbl_tvoc_val, LV_ALIGN_TOP_MID, 0, 32);
+
+  lv_obj_t *t_unit = lv_label_create(p_tvoc);
+  lv_label_set_text(t_unit, "ppb");
+  lv_obj_set_style_text_font(t_unit, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(t_unit, COL_MUTED, 0);
+  lv_obj_align(t_unit, LV_ALIGN_TOP_MID, 0, 58);
+
+  lbl_tvoc_range = lv_label_create(p_tvoc);
+  lv_label_set_text(lbl_tvoc_range, "-- / --");
+  lv_obj_set_style_text_font(lbl_tvoc_range, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(lbl_tvoc_range, COL_MUTED, 0);
+  lv_obj_align(lbl_tvoc_range, LV_ALIGN_BOTTOM_MID, 0, 2);
+
+  lv_obj_t *p_bot = make_panel(scr, UI_M, UI_BOT_Y, UI_BOT_W, UI_BOT_H);
+
+  lv_obj_t *info = lv_obj_create(p_bot);
+  lv_obj_set_size(info, UI_INFO_W, UI_BOT_H - 12);
+  lv_obj_align(info, LV_ALIGN_LEFT_MID, 0, 0);
+  lv_obj_set_style_bg_opa(info, LV_OPA_TRANSP, 0);
+  lv_obj_set_style_border_width(info, 0, 0);
+  lv_obj_set_style_pad_all(info, 0, 0);
+  lv_obj_clear_flag(info, LV_OBJ_FLAG_SCROLLABLE);
+
+  lbl_aqi = lv_label_create(info);
+  lv_label_set_text(lbl_aqi, "WARMUP");
+  lv_obj_set_style_text_font(lbl_aqi, &lv_font_montserrat_14, 0);
+  lv_obj_set_style_text_color(lbl_aqi, COL_WARN, 0);
+  lv_obj_set_width(lbl_aqi, UI_INFO_W);
+  lv_label_set_long_mode(lbl_aqi, LV_LABEL_LONG_CLIP);
+  lv_obj_align(lbl_aqi, LV_ALIGN_TOP_LEFT, 0, 0);
+
+  bar_aqi = lv_bar_create(info);
+  lv_obj_set_size(bar_aqi, UI_INFO_W - 4, 8);
+  lv_obj_align(bar_aqi, LV_ALIGN_TOP_LEFT, 0, 20);
+  lv_bar_set_range(bar_aqi, 0, 100);
+  lv_bar_set_value(bar_aqi, 0, LV_ANIM_OFF);
+  lv_obj_set_style_bg_color(bar_aqi, COL_ARC_BG, LV_PART_MAIN);
+  lv_obj_set_style_bg_opa(bar_aqi, LV_OPA_COVER, LV_PART_MAIN);
+  lv_obj_set_style_radius(bar_aqi, 4, LV_PART_MAIN);
+  lv_obj_set_style_bg_color(bar_aqi, COL_WARN, LV_PART_INDICATOR);
+  lv_obj_set_style_radius(bar_aqi, 4, LV_PART_INDICATOR);
+
+  lbl_eco2_lvl = lv_label_create(info);
+  lv_label_set_text(lbl_eco2_lvl, "eCO2 --");
+  lv_obj_set_style_text_font(lbl_eco2_lvl, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(lbl_eco2_lvl, COL_MUTED, 0);
+  lv_obj_set_width(lbl_eco2_lvl, UI_INFO_W);
+  lv_label_set_long_mode(lbl_eco2_lvl, LV_LABEL_LONG_CLIP);
+  lv_obj_align(lbl_eco2_lvl, LV_ALIGN_TOP_LEFT, 0, 34);
+
+  lbl_tvoc_lvl = lv_label_create(info);
+  lv_label_set_text(lbl_tvoc_lvl, "TVOC --");
+  lv_obj_set_style_text_font(lbl_tvoc_lvl, &lv_font_montserrat_12, 0);
+  lv_obj_set_style_text_color(lbl_tvoc_lvl, COL_MUTED, 0);
+  lv_obj_set_width(lbl_tvoc_lvl, UI_INFO_W);
+  lv_label_set_long_mode(lbl_tvoc_lvl, LV_LABEL_LONG_CLIP);
+  lv_obj_align(lbl_tvoc_lvl, LV_ALIGN_TOP_LEFT, 0, 48);
+
+  chart = lv_chart_create(p_bot);
+  lv_obj_set_size(chart, UI_CHART_W, UI_BOT_H - 16);
+  lv_obj_align(chart, LV_ALIGN_RIGHT_MID, 0, 0);
+  lv_chart_set_type(chart, LV_CHART_TYPE_LINE);
+  lv_chart_set_point_count(chart, HISTORY_LEN);
+  lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, 400, ECO2_ARC_MAX);
+  lv_chart_set_range(chart, LV_CHART_AXIS_SECONDARY_Y, 0, TVOC_ARC_MAX);
+  lv_chart_set_update_mode(chart, LV_CHART_UPDATE_MODE_SHIFT);
+  lv_obj_set_style_bg_color(chart, COL_CHART_BG, 0);
+  lv_obj_set_style_bg_opa(chart, LV_OPA_COVER, 0);
+  lv_obj_set_style_border_color(chart, COL_EDGE, 0);
+  lv_obj_set_style_border_width(chart, 1, 0);
+  lv_obj_set_style_radius(chart, 8, 0);
+  lv_obj_set_style_pad_all(chart, 4, 0);
+  lv_obj_set_style_line_width(chart, 2, LV_PART_ITEMS);
+  lv_chart_set_div_line_count(chart, 2, 4);
+  lv_obj_set_style_line_color(chart, COL_EDGE, LV_PART_MAIN);
+  lv_obj_set_style_line_opa(chart, LV_OPA_40, LV_PART_MAIN);
+  ser_eco2 = lv_chart_add_series(chart, COL_ECO2, LV_CHART_AXIS_PRIMARY_Y);
+  ser_tvoc = lv_chart_add_series(chart, COL_TVOC, LV_CHART_AXIS_SECONDARY_Y);
+
+  lv_obj_move_foreground(title);
+  lv_obj_move_foreground(lbl_uptime);
+  lv_obj_move_foreground(lbl_status);
+  lv_obj_move_foreground(led_status);
+  lv_obj_move_foreground(lbl_hint);
+}
+
+static void refresh_meta(void) {
+  char buf[40];
+  uint32_t up = millis() / 1000;
+  lv_snprintf(buf, sizeof(buf), "up %02lu:%02lu  bl%u",
+              (unsigned long)(up / 60), (unsigned long)(up % 60), (unsigned)bright_level);
+  lv_label_set_text(lbl_uptime, buf);
+
+  if (hint_until_ms && (int32_t)(millis() - hint_until_ms) >= 0) {
+    hint_until_ms = 0;
+    lv_obj_add_flag(lbl_hint, LV_OBJ_FLAG_HIDDEN);
+  }
+
+  if (!iaq_ready) {
+    uint32_t left = WARMUP_SEC - (millis() - boot_ms) / 1000;
+    if ((int32_t)left < 0) left = 0;
+    lv_snprintf(buf, sizeof(buf), "WARM %lus", (unsigned long)left);
+    lv_label_set_text(lbl_status, buf);
+    lv_led_set_color(led_status, COL_WARN);
+  } else if (sensor_ok) {
+    uint32_t age = (millis() - last_ok_ms) / 1000;
+    lv_snprintf(buf, sizeof(buf), "LIVE %lus", (unsigned long)age);
+    lv_label_set_text(lbl_status, buf);
+    lv_led_set_color(led_status, COL_OK);
+  }
+}
+
+static void update_ui(bool ok) {
+  char buf[32];
+
+  if (ok && !isnan(disp_eco2) && !isnan(disp_tvoc)) {
+    lv_color_t ec = eco2_color(disp_eco2);
+    lv_color_t tc = tvoc_color(disp_tvoc);
+
+    lv_snprintf(buf, sizeof(buf), "%.0f", disp_eco2);
+    lv_label_set_text(lbl_eco2_val, buf);
+    lv_obj_set_style_text_color(lbl_eco2_val, ec, 0);
+    lv_obj_set_style_arc_color(arc_eco2, ec, LV_PART_INDICATOR);
+    anim_arc(arc_eco2, (int)lroundf(constrain(disp_eco2, 0.0f, (float)ECO2_ARC_MAX)));
+
+    lv_snprintf(buf, sizeof(buf), "%.0f", disp_tvoc);
+    lv_label_set_text(lbl_tvoc_val, buf);
+    lv_obj_set_style_text_color(lbl_tvoc_val, tc, 0);
+    lv_obj_set_style_arc_color(arc_tvoc, tc, LV_PART_INDICATOR);
+    anim_arc(arc_tvoc, (int)lroundf(constrain(disp_tvoc, 0.0f, (float)TVOC_ARC_MAX)));
+
+    lv_snprintf(buf, sizeof(buf), "%.0f / %.0f", min_eco2, max_eco2);
+    lv_label_set_text(lbl_eco2_range, buf);
+    lv_snprintf(buf, sizeof(buf), "%.0f / %.0f", min_tvoc, max_tvoc);
+    lv_label_set_text(lbl_tvoc_range, buf);
+
+    lv_label_set_text(lbl_eco2_lvl, eco2_level_text(disp_eco2));
+    lv_obj_set_style_text_color(lbl_eco2_lvl, ec, 0);
+    lv_label_set_text(lbl_tvoc_lvl, tvoc_level_text(disp_tvoc));
+    lv_obj_set_style_text_color(lbl_tvoc_lvl, tc, 0);
+
+    lv_color_t ac = aqi_color(disp_eco2, disp_tvoc);
+    lv_label_set_text(lbl_aqi, aqi_text(disp_eco2, disp_tvoc));
+    lv_obj_set_style_text_color(lbl_aqi, ac, 0);
+    anim_bar(bar_aqi, aqi_score(disp_eco2, disp_tvoc));
+    lv_obj_set_style_bg_color(bar_aqi, ac, LV_PART_INDICATOR);
+
+    lv_chart_set_next_value(chart, ser_eco2, (int32_t)lroundf(disp_eco2));
+    lv_chart_set_next_value(chart, ser_tvoc, (int32_t)lroundf(disp_tvoc));
+    refresh_meta();
+  } else {
+    lv_label_set_text(lbl_aqi, "ERROR");
+    lv_obj_set_style_text_color(lbl_aqi, COL_BAD, 0);
+    lv_label_set_text(lbl_status, "ERR");
+    lv_led_set_color(led_status, COL_BAD);
+  }
+}
+
+static void read_sgp(void) {
+  if (!sgp.IAQmeasure()) {
+    fail_streak++;
+    Serial.printf("SGP30 fail(%u)\n", fail_streak);
+    if (fail_streak >= SGP_FAIL_TOLERANCE) {
+      sensor_ok = false;
+      update_ui(false);
+    }
+    return;
+  }
+
+  fail_streak = 0;
+  sensor_ok = true;
+  last_ok_ms = millis();
+
+  float eco2 = (float)sgp.eCO2;
+  float tvoc = (float)sgp.TVOC;
+
+  if (!iaq_ready) {
+    if ((millis() - boot_ms) / 1000 >= WARMUP_SEC) {
+      iaq_ready = true;
+      show_hint("IAQ ready", 1200);
+    } else {
+      /* Still show raw warmup readings */
+    }
+  }
+
+  disp_eco2 = ema(disp_eco2, eco2);
+  disp_tvoc = ema(disp_tvoc, tvoc);
+
+  if (isnan(min_eco2) || disp_eco2 < min_eco2) min_eco2 = disp_eco2;
+  if (isnan(max_eco2) || disp_eco2 > max_eco2) max_eco2 = disp_eco2;
+  if (isnan(min_tvoc) || disp_tvoc < min_tvoc) min_tvoc = disp_tvoc;
+  if (isnan(max_tvoc) || disp_tvoc > max_tvoc) max_tvoc = disp_tvoc;
+
+  Serial.printf("eCO2=%.0f(%.0f) ppm  TVOC=%.0f(%.0f) ppb\n",
+                disp_eco2, eco2, disp_tvoc, tvoc);
+  update_ui(true);
+}
+
+void setup() {
+  Serial.begin(115200);
+  delay(200);
+  boot_ms = millis();
+
+  ledcSetup(0, 5000, 8);
+  ledcAttachPin(TFT_BL_PIN, 0);
+  set_backlight(2);
+
+  Serial.println("CYD LVGL SGP30 Air Quality Dashboard");
+  Serial.printf("LVGL %d.%d.%d  SDA=GPIO%d SCL=GPIO%d\n",
+                lv_version_major(), lv_version_minor(), lv_version_patch(),
+                I2C_SDA, I2C_SCL);
+
+  Wire.begin(I2C_SDA, I2C_SCL);
+  Wire.setClock(100000);
+
+  if (!sgp.begin()) {
+    Serial.println("SGP30 not found — check wiring (SDA22/SCL27)");
+  } else {
+    Serial.printf("SGP30 OK  serial 0x%04X%04X\n",
+                  sgp.serialnumber[0], sgp.serialnumber[1]);
+    /* Absolute humidity optional; skip until DHT available */
+  }
+
+  lv_init();
+
+  touchscreenSPI.begin(XPT2046_CLK, XPT2046_MISO, XPT2046_MOSI, XPT2046_CS);
+  touchscreen.begin(touchscreenSPI);
+  touchscreen.setRotation(2);
+
+  lv_display_t *disp = lv_tft_espi_create(240, 320, draw_buf, sizeof(draw_buf));
+  lv_display_set_rotation(disp, LV_DISPLAY_ROTATION_270);
+
+  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_ui();
+  delay(200);
+  last_sgp_ms = 0;
+}
+
+void loop() {
+  uint32_t now = millis();
+  if (now - last_sgp_ms >= SGP_READ_MS) {
+    last_sgp_ms = now;
+    read_sgp();
+  }
+
+  static uint32_t last_meta_ms = 0;
+  if (now - last_meta_ms >= 1000) {
+    last_meta_ms = now;
+    refresh_meta();
+  }
+
+  lv_timer_handler();
+  lv_tick_inc(5);
+  delay(5);
+}