qpaperOS — E-Ink Smartwatch Firmware for T-Wrist
A minimal open-source smartwatch firmware for the LILYGO T-Wrist E-Paper with 3D-printable case, always-on time display, battery status, and deep-sleep for ~4-day battery life.
Overview
qpaperOS is an open-source smartwatch firmware for the LILYGO T-Wrist E-Paper ESP32 development board. The project turns the bare board into a fully functional, wrist-wearable smartwatch with a 3D-printed enclosure and 22 mm watch strap.
The E-Paper display stays always-on showing the current time and date — the ESP32 wakes from deep sleep every minute to refresh the display, achieving around 3–4 days of battery life with a 250 mAh LiPo.
Features
- Always-on time and date display (no blank screen thanks to e-ink)
- Battery percentage indicator
- Deep sleep between updates for maximum battery efficiency
- 3D-printable case (FreeCAD source included) with bottom plate and side buttons
- 22 mm standard watch strap compatible
- PlatformIO / Arduino framework build
Hardware
- LILYGO T-Wrist E-Paper (ESP32 + 1.54" e-paper display)
- 250 mAh 1S LiPo battery
- 3D-printed shell (M2 screws)
- 22 mm watch strap
Build
Flash with PlatformIO. The repository includes the full source code, 3D models (STL + FreeCAD), and assembly instructions. This project was featured on Hackaday.
Gallery
The repo contains 7 photos of the completed build in assets/photos/.
