When the alarm time arrives, the OLED flips its colors, flashes a wake up message along with the time, and the passive piezo buzzer lets out a steady, high pitched beep. Pressing the lower of the two tactile buttons stops the noise and brings the normal clock face back. The same little screen also counts up by seconds and shows the room temperature in a top bar.
The hardware is refreshingly simple: an ESP32 driving a 0.96 inch OLED, an LM35DZ for the temperature, the buzzer and two pushbuttons, all linked with jumper wires on a breadboard next to a laptop. The buttons open a configuration menu with separate entries for the alarm hour and the alarm minute, and saving a time switches the alarm on, shown as ON, before the display returns to the clock view.
What stands out to me is that the alarm flow is complete and demonstrably working. At 11:40:00 the inversion and flashing happened exactly on schedule, and the screen read 11:40:05 after the buzzer was silenced. A snooze feature is included as well, and the full code has been published on GitHub. The maker also said the idea was their own but that the code was written with AI, which strikes me as an honest way to work on a hobby build.
One thing is left open: the temperature reading in the top bar is labeled OpenWeather, yet nothing explains why a value coming from an LM35DZ sensor carries that label. That is the loose end I would most like to see cleared up.