A clock built from an ESP32 and a 7×7 flipdot display by Alfa-Zeta, synchronising time over WiFi using NTP. The display is driven over RS485 through a MAX485 transceiver, with a buck converter stepping the display’s 24V supply down to 3.3V for the logic.
It is a PlatformIO project, and includes a FLIPDOTS library I wrote for graphics, fonts, and talking to the display. freeRTOS schedules the time updater and spreads work across the ESP32’s two cores, so the display keeps animating while WiFi and Bluetooth work happens.
WiFi credentials, timezone, and the daylight savings offset are set over Bluetooth on each boot; once configured they are saved to flash and reused, and if nothing connects within ten seconds the device falls back to its last working configuration. The enclosure was designed in Fusion 360, laser cut from 5.33mm plywood, and stained black.
A variant, FLIPDOTS-Weather, runs the same hardware but shows weather information instead of the time.
