ESP32 CYD Weather Station

Touch-enabled weather station for the ESP32-2432S028R ("Cheap Yellow Display" / CYD). Fetches real-time weather from OpenWeatherMap, swaps day/night JPEG backgrounds from an SD card, persists your city across reboots.

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Why this exists

The CYD is a ~$10 ESP32 board with a 2.8" 320×240 ILI9341 touch display built in, making it a natural fit for a standalone weather widget. This project uses TFT_eSPI directly (no LVGL, no heavy UI framework) with XPT2046 touch calibration, NVS persistent storage, and JPEG backgrounds loaded from the SD slot — a practical demonstration of what the hardware can do with minimal dependencies.

Hardware

• ESP32-2432S028R (CYD) — tested on the diymalls 2.8" variant; hardware clones may need pin changes
• Micro SD card — FAT32, ≤32 GB
• Micro USB cable — power and programming

Dependencies

Install via Arduino Library Manager:

1. TFT_eSPI by Bodmer
2. XPT2046_Touchscreen by Paul Stoffregen
3. ArduinoJson by Benoit Blanchon (v7+)
4. TJpg_Decoder by Bodmer

Installation

1. Configure TFT_eSPI

Edit Documents/Arduino/libraries/TFT_eSPI/User_Setup.h:

#define ILI9341_DRIVER
#define TFT_MISO 12
#define TFT_MOSI 13
#define TFT_SCLK 14
#define TFT_CS   15
#define TFT_DC    2
#define TFT_RST  -1
#define TFT_BL   21
#define TFT_BACKLIGHT_ON HIGH
#define SPI_FREQUENCY       55000000
#define SPI_READ_FREQUENCY  20000000
#define SPI_TOUCH_FREQUENCY  2500000

2. Prepare the SD card

1. Format to FAT32.
2. Copy day-aero-fit.JPG and night-aero-fit.JPG from sd card files/ to the root of the card.
3. Custom backgrounds must be 480×270 px JPEG. Night falls back to the day image if missing.

3. Get an OpenWeatherMap API key

Free tier at openweathermap.org is sufficient.

4. Set credentials

# Copy and fill in:
cp secrets.example.h secrets.h

#define WIFI_SSID          "YOUR_SSID"
#define WIFI_PASSWORD      "YOUR_PASS"
#define OWM_API_KEY        "YOUR_KEY"
#define DEFAULT_CITY_NAME  "New York,NY,US"

secrets.h is gitignored — credentials never leave your machine.

5. Flash

Select ESP32 Dev Module in Arduino IDE, connect via USB, click Upload.

Usage

• Change city: tap the city icon (bottom right) → on-screen keyboard → OK
• Recalibrate touch: tap the calibration button (bottom left) → follow the dots
• Data refreshes every 10 minutes; WiFi reconnects automatically on drop

Troubleshooting

Symptom	Fix
secrets.h: No such file	Copy secrets.example.h → secrets.h
"SD not detected"	Reformat to FAT32; try a different card
White screen	Check TFT_eSPI pin config in User_Setup.h
Touch not working	Confirm XPT2046_Touchscreen is installed
Night image never shows	Put night-aero-fit.JPG in the SD card root

Status

Stable. Works as described on the tested hardware. Not hardened for production use.

License

The Unlicense — public domain.