patriandClaude Opus 5.5
66f70c0cc1
- speed page: 120 px antialiased number (lv_font_conv) + 0-200 km/h arc gauge over ezgif-5-cb56986bc7.gif (embedded via board_build.embed_files) - swipe-left menu: scan, OBD-like adapters first, tap to select; adapter remembered in NVS, auto-connect at boot and reconnect every 3 s - ELM327 init ATZ/ATE0/ATL0/ATS0/ATH0/ATSP0/0100, then 010D polling - shared ini: -DLV_LVGL_H_INCLUDE_SIMPLE for generated fonts Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
OBD Speed (JC3636W518)
Vehicle speed from an ELM327 over BLE, shown as a big number + arc gauge on top of an animated GIF.
Uses the shared board library and LVGL 9.6 (../shared), NimBLE-Arduino 2.5.1.
Use
- Speed page — speed in km/h (
--= no data: not connected, or ignition off), arc gauge 0–200 km/h, status at the bottom (adapter name when running, otherwise what it is doing). - Swipe left → adapter menu — scans while open. OBD-like adapters (name OBD/ELM/…, or service FFF0/FFE0/18F0) are listed first in green. Tap one to select it: it is remembered (NVS) and connected immediately. Forget clears the remembered adapter, Done (or swipe right) returns to the speed page.
- On power-up the remembered adapter is connected automatically; if the link drops or the adapter is not there (car off), it retries every 3 s. With no adapter remembered, the device starts on the menu page.
How it talks to the ELM327
Service FFF0, notifications + commands on FFF1 (verified with the user's "OBDII" adapter, see
../11-BLE-Scanner/results/2026-10-23_car_test.txt); other adapters: first notify+write pair.
Init: ATZ, ATE0, ATL0, ATS0, ATH0, ATSP0, 0100; then 010D (speed) is polled continuously.
Serial (115200) prints status changes as [obd] ....
Files
| File | What |
|---|---|
src/main.cpp |
LVGL UI (tileview: speed page + menu page) |
src/obd_link.cpp/.h |
BLE scan, connect/reconnect, ELM327 init and speed polling (background task on core 0) |
src/font_speed_120.c |
Montserrat Medium 120 px, digits and -, 4 bpp (generated with lv_font_conv, see header) |
data/bg.gif |
Background (ezgif-5-cb56986bc7.gif, 360×360), linked into the firmware via board_build.embed_files |
Replace data/bg.gif with any 360×360 GIF to change the background (keep it under ~3 MB).