What is s3ntry?

S3NTRY is custom smartwatch firmware, meaning the low level software that runs directly on a specific piece of hardware, in this case the Waveshare ESP32-S3 Touch AMOLED 2.06 inch development board. Instead of buying a finished commercial smartwatch, you flash this software onto the hardware board yourself to turn it into a fully working smartwatch. The firmware packs in a surprising number of features. It includes four distinct watchfaces, each with its own visual style: a circuit board look with animated signal traces and a small tap based game, a bold headline style layout with scrolling data, a dense terminal style screen showing lots of live system data at once, and an astronomical view that cycles between a clock, moon phases, a solar system view of all nine planets, and a night sky of stars and constellations. All four themes can be recolored using four shared color schemes from the settings menu. The watch connects to an iPhone over Bluetooth to receive notifications, keeps a history of the last 20 of them, and lets you mute specific apps. It can control music playback on the paired iPhone, or play MP3 and WAV files directly from a microSD card using its own built in player with shuffle and repeat. It can also act as a wireless trackpad and keyboard for a paired computer, and it includes a Game Boy emulator that plays original Game Boy ROM files from the SD card, complete with save states. Productivity features round it out: alarms, countdown timers, a stopwatch, and a to do list that can hold up to 500 items, syncs with iPhone Reminders, and saves to the SD card so it survives reboots. The README claims 10 or more hours of battery life with Bluetooth active and notifications on, achieved by automatically sleeping the display and waking when the wrist is raised. This is a project for hardware hobbyists who are comfortable flashing custom firmware onto a specific microcontroller board, not a ready made consumer product.