# OBD Display (2024 experiments)

Leftovers of the earlier attempt to show car speed from an ELM327 on the JC3636W518.
The 2024 design needed a second (classic) ESP32 as a Bluetooth-Classic → WiFi bridge; that bridge, the ELMulator
and the WiFi speed sketch were removed on 2026-10-23 (still in git history) — the ELM327 is now read directly over BLE,
see `../12-OBD-Speed`.

## Projects (PlatformIO, LVGL 9.6.0, shared library in `../shared`)
| Folder | What it does |
|---|---|
| `display_gif_embedded/` | GIF compiled into firmware (`src/loligod.c`, 2.2 MB GIF → 3.5 MB firmware, `default_16MB.csv`). Plays at full GIF speed (~23.8 fps, 53 % CPU). GIF starts without SD card. |
| `display_gif_sd/` | `wallpaper.gif` from the SD card, loaded into PSRAM once and played from memory (~15 fps for the current file). |
| `assets/gifs/` | GIF files (`dump/` = unused collection) |
| `_archive/lvgl9_broken/` | Unfinished 2024 LVGL 9 port, does not compile |

## Build / upload
```
pio run -d display_gif_embedded -t upload       # flash (COM21)
pio device monitor -d display_gif_embedded      # serial: FPS / refresh / other / CPU once per second
```
(`pio` = `%USERPROFILE%\.platformio\penv\Scripts\pio.exe` if not on PATH.)

## Notes
- `display_gif_embedded/src/montserrat_100.c` (100 px digits font, 1 bpp) is present but not used.
- `display_gif_sd` returns early in `setup()` if the SD card fails to mount (black screen).