A mostly accurate 15 minute timer with a loud tick and a charming bell - use VLC and loop it.
Published on 22 Sep 2022 / In Film & Animation
Play in VLC media player and loop it - 15 minutes computer, 15 minutes other work etc. Or Strip out the audio as an MP3 and play it like that.
You can even play it at 1/2 or 1/4 speed for 30 minute and hour cycles.