My latest electronics project is an ESP32 based alarm clock with integrated webserver for configuration and setting alarms. By default shortly after midnight my home server (Zima board) will determine if it is working day or a holiday and set the alarm clock accordingly. I can change the setting manually from my phone, via a ready-made app that lets you configure curl calls.

The clock has three display modes: Normal time, countdown to alarm and Swatch Internet time. Countdown mode counts down to the currently set alarm if any and is indicated by displaying a dot in front of the shown time. If there is less than an hour to the alarm, the clock switches to minutes and seconds display.

I decided to use the Eclipse based ESP IDE for this project, as a more professional choice, compared to my previously used Arduino IDE.

In the beginning I used to have flickering issues with the MAX7219 LED matrix, which I solved by soldering a few capacitors. I’m planning on 3d printing my own case in an upcoming project.

Last modified on 2026-05-01