A portable pomodoro timer with a music player built in, running on an M5Stack Core2. Flip it over like an hourglass to start a session.
The two things I want during focused work are a timer and music, and I did not want them to be two devices or two apps. So it is one handheld: it plays from a microSD card while the timer runs, goes quiet on breaks, and syncs its library and session stats with a server at home over Wi-Fi.
The interaction is physical rather than menu-driven. Flip it over like an hourglass to start. Put it face down to pause. The IMU handles both, so you never have to look at it to use it.
| Board | M5Stack Core2: ESP32, touch display, speaker, microSD, MPU6886 IMU, Wi-Fi and Bluetooth |
| Firmware | PlatformIO with the Arduino framework, LVGL for the interface |
| Audio | MP3 and OGG off the card, out to the speaker or Bluetooth headphones |
| Server | Self-hosted FastAPI: playlists, file sync, session stats, auto-ingest |
| Layout | Monorepo: firmware/, server/, docs/ |
Five, selectable: digital, hourglass sand, ring, analog, and a candle that burns down. The hourglass is the one that made the flip gesture obvious.
These are the face designs at the display's real resolution of 320 by 240. They are drawings, not captures off the device, because the firmware currently boots to a splash screen and nothing else. They will be replaced with real screens once there are real screens to photograph.
Phase 0, scaffolding. The firmware boots to a splash screen on real hardware, the server answers a health check, and CI builds both halves on every push. Nothing is playing music yet.
The firmware builds and flashes to the Core2 and comes up to a splash screen. Not much to look at, but it closes the loop on toolchain, partition layout and board config, which is the part that usually eats the first week.
Partition table is custom for the 16 MB flash, since the stock layouts do not leave enough room for the app plus LVGL plus a filesystem.
One pipeline builds the firmware with PlatformIO and runs the server tests, so a change that breaks either one fails immediately.
Worth doing this early on a monorepo with two completely different toolchains. The alternative is finding out weeks later that the firmware has not compiled since some unrelated change to the Python side.