Tab5 Observatory

A feature-rich, data-dense weather and environment dashboard for the M5Stack Tab5 (ESP32-P4), built with Arduino and LVGL 8.x. Fourteen swipeable screens cover everything from live indoor air quality to real-time earthquake activity, astronomical data, tides, and space weather — all in a polished dark-themed UI on the Tab5's 1280×720 MIPI-DSI display.

https://youtu.be/P9kC9wAIuWU?si=Une-ShOrxgz4CorA

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Features

14 Swipeable Screens

#	Screen	Description
0	Clock	Large HH:MM:SS, date, indoor conditions row, current weather panel, 5-slot forecast outlook strip
1	Local Sensor	BME688 live readings — temperature, humidity, pressure cards; IAQ score; comfort panel with dew point and heat index; 8-hour trend chart
2	Current Weather	WeatherAPI conditions hero, UV/AQI card, detail grid, hourly sparkline
3	3-Day Forecast	Daily forecast cards with temperature, weather icon, wind, UV, rain chance
4	Astronomy	Animated sun arc canvas, moon phase disc, rise/set/noon countdowns, 6-field data panels
5	Solar Elevation	Full 24-hour solar elevation curve — twilight bands, current sun position, civil/nautical/astronomical twilight markers
6	Seasons	NOAA-style Southern Hemisphere Earth orbit diagram with current position
7	Lunar Orbit	Observatory-style lunar orbit canvas with phase timeline strip
8	Planets Tonight	AstronomyAPI planet visibility list with sky compass polar plot
9	Weather Alerts	BOM/WeatherAPI active warnings with severity colour coding
10	Space Weather	BOM Space Weather — K-index, A-index, Dst, aurora status, 24-hour K bar chart
11	Sensor Statistics	Tabbed temp/humidity/pressure stats with 8h/24h/7d time windows; Today/Yesterday/7-Day/Trend cards; SD-backed history
12	Tides	Fort Denison (Sydney Harbour) tidal curve, H/L markers, next tide countdown — reads pre-generated CSV from SD card
13	Earthquake Activity	Live USGS earthquake map for Australia/Pacific — depth-coloured dots, magnitude labels, 7d/24h/M4+ filters, largest event panel
+	Settings	Brightness, timeout, refresh intervals, system info — battery, WiFi, memory

Navigation

• Swipe left/right — move between screens 0–13 (wraps)
• Long-press anywhere — open quick-pick overlay menu
• Settings button — footer button on any screen

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Hardware

Component	Details
Board	M5Stack Tab5 (ESP32-P4, 32MB PSRAM, 16MB Flash)
Display	5" 1280×720 MIPI-DSI touchscreen
Sensor	BME688 (ENV Pro Unit, Grove Port A — GPIO 53/54)
RTC	RX8130CE (I2C address 0x32, GPIO 31/32)
SD Card	SPI mode (SCK=43, MISO=39, MOSI=44, CS=42, 25MHz)
Battery	FB-NP-F550-B 7.2V 2S Li-ion 2200mAh (optional)

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Software Dependencies

Arduino Libraries

• M5Unified — board init, display, power management
• M5GFX — graphics foundation
• LVGL 8.4 — UI framework
• ArduinoJson v6 — JSON parsing (DynamicJsonDocument API)
• Bosch BME68x-Sensor-API — raw BME688 driver

APIs Used (all free tier)

API	Data	Refresh
WeatherAPI.com	Current weather, 3-day forecast, alerts, AQI	15 min
AstronomyAPI.com	Planet positions, moon data	6 hours
BOM Space Weather	K-index, A-index, Dst	30 min
USGS FDSNWS	Earthquake events	15 min
WorldTides / SD CSV	Tidal predictions	SD card (pre-generated)

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Project Structure

Tab5_WeatherDash/
├── Tab5_WeatherDash.ino    # Main sketch — setup(), loop(), fetch scheduling
├── ui_main.h               # Screen index defines, update function declarations
├── ui_main.cpp             # All 14 LVGL screens — build + update functions (~8500 lines)
├── config.h                # API keys, location, WiFi credentials
├── sensors.h / .cpp        # BME688 raw driver, open VOC IAQ algorithm
├── rtc_utils.h / .cpp      # RX8130CE RTC — direct I2C driver
├── sd_logger.h / .cpp      # SD logging, baseline persistence, history reload, extended stats
├── weather_api.h / .cpp    # WeatherAPI fetch + parse
├── astro_api.h / .cpp      # AstronomyAPI fetch + parse
├── space_weather_api.h/.cpp # BOM space weather fetch + parse
├── bom_warnings_api.h/.cpp # BOM weather warnings fetch + parse
├── earthquake_api.h / .cpp # USGS FDSNWS fetch + parse
└── earthquake_map_data.h   # Pre-computed coastline data (Natural Earth 110m)

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SD Card Layout

/
├── sensor/
│   ├── 2026-04-05.csv      # Daily sensor logs (5-min rows)
│   └── 2026-04-06.csv
├── config/
│   └── baseline.json       # IAQ baseline, pressure reference, cumulative runtime
└── tides.csv               # Pre-generated Fort Denison tidal data 2026–2027

The SD card must initialise before WiFi — the SDMMC/WiFi bus conflict on ESP32-P4 is unresolvable in SDMMC mode. This project uses SPI mode on the pins above to avoid the conflict entirely.

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Key Implementation Notes

ESP32-P4 Specific

• I2C: Use Wire.begin(53, 54) for Grove Port A — do NOT use TwoWire(1), it crashes on ESP32-P4
• Touch transform: Raw coords are portrait (720×1280); transform to landscape: lvgl_x = 1279 - raw_y, lvgl_y = raw_x
• LVGL driver structs must be static locals inside init functions — global static structs cause init order crashes
• LVGL tick: Use fixed lv_tick_inc(5) + delay(5) pattern
• TZ env var must be re-applied after configTime() — ESP32 resets it during NTP sync
• setExtOutput() with masks crashes the Tab5 power expander — avoid
• Board package: v3.2.6 has a known WiFi/SDIO crash bug; v2.1.4 is stable if issues arise

BME688 Sensor

• Forced mode: call fetchData() then getData() — do not use continuous mode
• IAQ algorithm: custom open implementation (Bosch BSEC2 is incompatible with ESP32-P4 single-float RISC-V ABI)
• I2C address: 0x77

Battery / Power

• Tab5 uses a 7.2V 2S Li-ion pack (FB-NP-F550-B), valid range 5500–8400mV
• Without battery, PMIC oscillates ~4280mV ↔ ~8380mV — detected by voltage range + swing stability check
• getBatteryVoltage() returns full 2S pack voltage in millivolts
• isCharging() is unreliable without a battery and must be suppressed in that state

LVGL Canvas Drawing

• Always use the canvas_line(canvas, x1, y1, x2, y2, colour, width) helper — do not call lv_canvas_draw_line() directly (different signature)
• lv_obj_get_width/height() returns stale values after lv_obj_clean() — use hardcoded constants
• lv_label_set_recolor must be enabled per-label for colour markup tags to work
• Middle dots (U+00B7) and em-dashes render as boxes in Montserrat — use ASCII pipe | and hyphen

Macro Name Clashes

A recurring issue: local variable names clash with Arduino/LVGL macros. Always prefix local layout constants with a screen abbreviation:

• PAD → SP_PAD, EQ_PAD, SS_PAD
• LIST_H → EQ_LIST_H
• Any short common word is at risk

Earthquake Map

• Coastlines from Natural Earth 110m TopoJSON
• Countries: AU, PNG, Indonesia, NZ, Philippines, Malaysia, Brunei, Solomons, Vanuatu, New Caledonia, Fiji, Timor-Leste
• 41 segments, 859 points — pre-converted to canvas pixel coordinates in earthquake_map_data.h
• Map bounds: 108–182°E, 55°S–22°N, 800×540px canvas in PSRAM

HTTP Fetching

• Chunked transfer encoding (content-length=-1) is common — getStreamPtr() returns raw chunk-encoded stream, don't parse directly
• For large responses: allocate PSRAM buffer, use stream->readBytes(buf, size) — single blocking call, no WDT risk
• For filtered responses: ArduinoJson DeserializationOption::Filter() dramatically reduces doc size requirements

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Configuration

Copy config.h.example to config.h and fill in:

#define WIFI_SSID        "your_ssid"
#define WIFI_PASSWORD    "your_password"
#define WEATHER_API_KEY  "your_weatherapi_key"
#define ASTRO_APP_ID     "your_astronomyapi_id"
#define ASTRO_APP_SECRET "your_astronomyapi_secret"
#define WEATHER_LOCATION "Sydney"
#define WEATHER_LAT      -33.8568
#define WEATHER_LON      151.2253

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Building

1. Install Arduino IDE 2.x
2. Add M5Stack board (3.2.6) package: https://m5stack.oss-cn-shenzhen.aliyuncs.com/resource/arduino/package_m5stack_index.json
3. Select board: M5Stack Tab5 (or ESP32P4 Dev Module if Tab5 not listed)
4. Install libraries via Library Manager: M5Unified, M5GFX, LVGL (8.4), ArduinoJson (6.x), Bosch BME68x-Sensor-API
5. Configure LVGL: copy lv_conf.h to your Arduino libraries folder
6. Set partition scheme: 16MB Flash (3MB APP/9.9MB FATFS) or similar with OTA
7. Flash size: 16MB, PSRAM: OPI PSRAM

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Tides Setup

The tides screen reads from /tides.csv on the SD card. Pre-generate this file using the WorldTides API or PYSEIDON for your tide station. Format:

datetime,height_m,type
2026-01-01T00:23:00+11:00,0.42,L
2026-01-01T06:15:00+11:00,1.31,H
...

For Fort Denison (Sydney Harbour), station ID is available via WorldTides or BOM.

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Screen Navigation Reference

Long-press anywhere → Quick-pick overlay (all 14 screens)
Swipe left  → previous screen (wraps 0→13)
Swipe right → next screen (wraps 13→0)
Settings footer button → Settings screen (not in swipe sequence)

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License

MIT License — see LICENSE

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Acknowledgements

• Natural Earth — coastline data for earthquake map
• USGS Earthquake Hazards Program — free earthquake API
• WeatherAPI.com — weather data
• AstronomyAPI.com — planetary positions
• Bureau of Meteorology — space weather and warnings
• M5Stack — Tab5 hardware and M5Unified library
• LVGL — embedded graphics library
• Bosch Sensortec — BME688 sensor and driver

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Built for Sydney, Australia. Location-specific elements (tides, weather location, coordinates) are easily changed in config.h.