patriandClaude Opus 5.5
4fc70f13d0
- third tile (swipe left from the menu): rotation buttons, saved in NVS, applied at boot - shared lib: setRotation() rotates only the panel and redraws; touch points are converted in touchpad_read() for the current rotation; getRotation() added Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
31 lines
2.0 KiB
Markdown
31 lines
2.0 KiB
Markdown
# OBD Speed (JC3636W518)
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Vehicle speed from an ELM327 over BLE, shown as a big number + arc gauge on top of an animated GIF.
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Uses the shared board library and LVGL 9.6 (`../shared`), NimBLE-Arduino 2.5.1.
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## Use
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- **Speed page** — speed in km/h (`--` = no data: not connected, or ignition off), arc gauge 0–200 km/h,
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status at the bottom (adapter name when running, otherwise what it is doing).
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- **Swipe left → adapter menu** — scans while open. OBD-like adapters (name OBD/ELM/…, or service FFF0/FFE0/18F0)
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are listed first in green. **Tap one** to select it: it is remembered (NVS) and connected immediately.
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**Forget** clears the remembered adapter, **Done** (or swipe right) returns to the speed page.
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- **Swipe left again → settings** — screen rotation 0 / 90 / 180 / 270 degrees (tap to apply; remembered in NVS, applied at boot).
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- On power-up the remembered adapter is connected automatically; if the link drops or the adapter is not
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there (car off), it retries every 3 s. With no adapter remembered, the device starts on the menu page.
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## How it talks to the ELM327
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Service `FFF0`, notifications + commands on `FFF1` (verified with the user's "OBDII" adapter, see
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`docs/2026-10-23_ble_scanner_car_test.txt`, made with the BLE scanner tool that was removed afterwards — in git history); other adapters: first notify+write pair.
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Init: `ATZ`, `ATE0`, `ATL0`, `ATS0`, `ATH0`, `ATSP0`, `0100`; then `010D` (speed) is polled continuously.
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Serial (115200) prints status changes as `[obd] ...`.
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## Files
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| File | What |
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|---|---|
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| `src/main.cpp` | LVGL UI (tileview: speed page + menu page) |
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| `src/obd_link.cpp/.h` | BLE scan, connect/reconnect, ELM327 init and speed polling (background task on core 0) |
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| `src/font_speed_120.c` | Montserrat Medium 120 px, digits and `-`, 4 bpp (generated with `lv_font_conv`, see header) |
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| `data/bg.gif` | Background (`ezgif-5-cb56986bc7.gif`, 360×360), linked into the firmware via `board_build.embed_files` |
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Replace `data/bg.gif` with any 360×360 GIF to change the background (keep it under ~3 MB).
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