Ask HN: Have you created programs for only your personal use?

I wrote a radio station-style audio playback system, because I didn't like the tiny few that existed for Mac OS

I work as a water engineer, specializing in building hydraulic models so water utilities can simulate their network.

A big part of that is calibrating them which can be time consuming, you look through hundreds of options. I create a few web based apps to help grind through these tasks but ultimately they were for my own use as a consultant to close projects quickly.

I did pull out the engine as its own open source library for other to use, and that ended up helping me get my current role where I can now maintain it and be paid at the same time.

https://github.com/modelcreate/epanet-js

I wrote an expense splitting web app that works with multiple currencies and can export transactions in a format compatible with GNU Cash (that I use) and Excel (that my partner uses). Before that we were using an existing solution (Tricount) but its limitations regarding currencies and export meant that we always made mistakes.

Yes - I wrote a full DVD authoring workflow to take weekly anime fansubs and produce finished DVDs for friends with either bad internet connections or who preferred to watch in their living rooms.

This was before having an HTPC or media center was a mainstream idea.

All you did was add in the video files sorted by file name in a subdirectory and add a main menu image template, a main menu audio file, and episode select image template (the layouts were static so that the same dvdauthor XML could be used) and it would stitch together a DVD with an intro video, main menu screen with subtitle, play, and episode select options, and generate episode select screens by taking thumbnails from the video files.

Last time I used it was about five years ago before same day/date streaming of anime really took off. I still hack on it from time to time. I don't really have a use for the output, but it's nice to maintain it as the tools it use change/update and as I learn new things.

I once wrote a program to scrape the logs from some printers so I could keep track of how much paper and ink was being used. It was just for fun but I showed it to my teammates and we ended up turning it into a leaderboard of who used the least amount of resources. Then they replaced the printers and I didn't feel like redoing it.