# Kronograf: aviation firmware for the T-Watch 2020

A from-scratch firmware for the LilyGO T-Watch 2020 with an aviation chronograph face, Back to the Future time circuits, bus departures, iPhone notifications and a network toolbox on the wrist.

- Category: Interface (mod)
- Device: [LilyGO T-Watch 2020](https://afterware.xyz/d/lilygo-t-watch-2020)
- Made by: [storagebits](https://github.com/storagebits) on GitHub
- Original: https://github.com/storagebits/kronograf
- On Afterware: https://afterware.xyz/p/kronograf-aviation-firmware-for-the-t-watch-2020

## Can I build this?

- Difficulty: Beginner
- AI-buildability: 5/5 (It is almost entirely firmware for an off-the-shelf watch, so AI tools can write the LVGL UI, network features and simulator, and you only flash it over USB.)
- Time: A few weeks
- Cost: $25–40
- Parts: ESP32, 1.3in SH1106 128x64 OLED
- Tools: PlatformIO, USB-to-serial adapter, macOS with SDL2 and CMake for simulator

Estimates based on the original write-up. How the AI-buildability score works: https://afterware.xyz/ai-buildability

## Starter prompt

```
Based on "Kronograf: aviation firmware for the T-Watch 2020" on Afterware: https://afterware.xyz/p/kronograf-aviation-firmware-for-the-t-watch-2020

I have a LilyGO T-Watch 2020 V1 with an ESP32 and a 240x240 ST7789 display. Using PlatformIO and LVGL 8, write a watch firmware with a swipeable analog chronograph face showing the time and battery level, and a second face with a dark red time-only layout. Read the accelerometer for wrist-raise wake and keep the code split into hardware abstraction and UI modules.
```

## Story

Kronograf replaces the stock software on the LilyGO T-Watch 2020 with a firmware written from scratch on LVGL 8.3 and ESP32. The watch gets three faces, including an aviator chronograph and a "time circuits" face with three 7-segment rows, plus a launcher of nine-app pages drawn like sub-dials.

Beyond the faces, the firmware adds weather from Open-Meteo, real-time STM bus departures from a GTFS-realtime feed, iPhone notifications over ANCS with clear and decline actions, and a network toolbox covering Wi-Fi analysis, ping, traceroute, LAN scan and speed test. A TV remote uses the watch's infrared LED.

The project also includes a macOS simulator that builds the same interface, so screens can be checked and screenshotted without the hardware. Prebuilt binaries are published on the release page.

## Resources

- [Repository](https://github.com/storagebits/kronograf)
- [Releases (prebuilt firmware)](https://github.com/storagebits/kronograf/releases)
- [My-TTGO-Watch](https://github.com/sharandac/My-TTGO-Watch)

Tags: lvgl, esp32, smartwatch, ble, ancs, watchface, t-watch

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