UNA analog face

AnalogFace is a custom watch face I wrote for the UNA Watch using the UNA Watch SDK. It runs as an app on the watch's 240×240 reflective memory LCD — a screen with only four levels per colour channel, which is why the dial is drawn in flat, high-contrast shapes rather than gradients.

The face itself is simple: large hour numerals around the outside, hollow hour and minute hands with red accent stripes, and concentric teal rings around a black centre. The complications in the middle are the things I actually want at a glance — the month, a big day-of-week and date, today's step count, and a battery dot that goes from green to yellow to red.

The bottom of the dial is a readout that cycles through pages: next sunrise or sunset (computed on the watch from the last GPS fix), altitude, heart rate, SpO₂, ambient temperature and GPS speed. Each page only powers its sensor while it is showing, so the face is easy on the battery.

As with SleepVue, I built this with OpenCode driving the Kimi 3 model — from setting up the toolchain and SDK to writing the face itself and generating all of the graphics and icons. Total AI credit cost: $45.44.

Buttons

• Top right — stopwatch: start, stop, clear. While it runs the hour hand hides and the minute hand becomes the chrono sweep, with the elapsed time on a black badge.
• Top left — shows a black background behind the bottom readout for five seconds so it can be read past the hands; press again within that window to cycle to the next page.
• Bottom right — exit the app.

Under the hood

• C++ on the UNA SDK, with the dial drawn in TouchGFX
• Two processes: a service that owns the clock, stopwatch, sun-event math and sensor subscriptions, and a GUI that renders the dial and arbitrates what the bottom slot shows
• Sunrise and sunset use the NOAA solar equations against a GPS fix persisted on the watch
• Built with CMake and the ST ARM GCC toolchain, packed into a .uapp and copied onto the watch over USB