LilyPhone1 — Phone App Firmware for LILYGO T-Deck Pro
A phone-inspired LVGL UI firmware for the LILYGO T-Deck Pro that turns the e-paper + LTE handheld into a functional phone interface with cellular modem support, GPS, touch, audio, and a web-based UI built with PlatformIO.
Overview
LilyPhone1 is an experimental phone application firmware for the LILYGO T-Deck Pro. It leverages the T-Deck Pro's combination of e-paper display, 4G LTE modem (A7682), GPS (TinyGPS++), touchscreen (CSTXXX), audio, and power management (XPowersPPM + BQ27220 fuel gauge) to build a functional handheld phone experience with an LVGL-rendered UI.
Hardware Features Used
- E-paper display — GxEPD2 3.1" 240×320 with partial and full refresh modes
- 4G LTE modem — TinyGSM modem for cellular calls and data (A7682 variant)
- GPS — TinyGPS++ for location tracking
- Touchscreen — CSTXXX capacitive touch driver
- Audio — onboard audio support for calls
- Power management — XPowersPPM and BQ27220 fuel gauge integration
- Settings persistence — stored using ESP32's Preferences API
Technical Details
Built with PlatformIO using the Arduino framework. The UI is rendered with LVGL and the project includes a separate ui_phone1 module for screen layouts. The src/peripherals/ directory manages hardware initialization for each subsystem, keeping the main loop clean. Still in active development — currently targeted at the T-Deck Pro 4G hardware variant.
