Ask HN: Most interesting tech you built for just yourself?

Maybe not interesting, but a slideshow application that is much faster and more memory efficient than anything I could find.

Image viewers I tried all beachballed constantly, were slow to respond if they even did, had many bugs, and required many interactions and pixel hunting to interact with.

It emphasizes instant response even when working with 10s if thousands of very large photos, and a UI that eliminates or reduces required interactions, and integrates with finder smartly.

It defaults to opening folders or images fullscreen and round robins windows across displays. The UI is a 3x3 button grid overlay that auto hides, the window name is the the last three parts of the file path. There is gesture support, but I don’t use it because focus is a pain to deal with.

JPEG decoding is memory intensive so there is a shared rendering process so the parallelism can be managed and memory uses isn’t duplicated.

A shared cache process contains bitmaps of images scaled to screen size that are stored on disk. This kind of assumes you are on a fast flash drive like an MBP where flash is basically as fast as memory.

The cache is a 100 element LRU in front of Caffeine (W-Tiny LFU) and all the cache state is persistent including Caffeine so it can remember the LRU and adaptive cache state across restarts.

Prefetching scales the previous and next five images in parallel so you can click forward/next and it is instant every time.

When you turn shuffle off it plays forward from the image you were on. You can click a button and it will loop all files on a directory.

You can open multiple files or directories from finder and it will play all nested files in order.

The order is a natural order that parses numbers so if the numbers aren’t padded you still get the correct order.

Ended up using JavaFX which works surprisingly well. Fast JPEG decoding, working HiDPI, window resizing and movement renders very nicely.

Not sure how interesting they are for others, but i built a few things to keep myself accountable and track progress on parts of my life I wanted to improve - small parts, but things I just kept procrastinating on.

1. I built a small web app to provide a cycling routine to help me go from zero miles and overweight to riding a century (100 miles) this summer. I used to ride move frequently when I was younger and my longest ride was 87 miles with camping gear on my back. But 2 decades, a web dev job, and 2 kids later I am lucky to be able to get 10 miles per week for any consistent stretch of time. The app takes my recent riding skill and athleticism, and creates a 6 week riding 'program' for me basing itself on # of miles per day for the 6 weeks and increasing each week until the culmination of the 100 mile ride, allowing for 2 rest days each week. It isn't the most robust but it's gotten me motivated to ride this summer.

2. I built a reading list tracker that I can add the books I want to read for myself and my kids. It suggests which book to read next if I can't decide. It tracks # of books to read, # completed, # of pages & hours to read (so I can see how unlikely it is that I will ever finish my list or can plan time accordingly to know through the list systematically), allows me to categorize the books, and lists them as MY reading list or a list to read with my KIDS.

3. A European travel planner that I track country and city costs with, can create custom travel itineraries, which then will show actual costs for the itinerary based on the costs I am tracking/inputting for cities/countries/attractions.

4. More fun for myself and friends: A soccer scores predictor game. We each follow teams and clubs from various world leagues, and pick the scores for upcoming matches. Then the app scores us based on our predictions and we have annual competitions with each other. I built this before these were as popular as they are now, and well before the likes of FanDuel/gambling sites.

Starting in HS and continuing for years I developed the first and only complete software package I’ve ever made, for my father. He’s a EE and was doing a lot of his board design in excel — if I remember this meant he then needed to map the excel design onto a layout program to connect all the parts; the layout program generates a netlist and the netlist then goes to the actual layout person who figures out the final position of parts/traces on the board.

He hired me to make a VBA program that generates the netlist directly from excel. Refined it over the years and I believe he still uses it to this day. He can turn around a design in far keat time than it used to take.

I’m no EE — and it’s been probably 15 years since I’ve touched that code — so I may have gotten some details wrong here. But it was a cool project to work on and taught me a lot about code!

Hard to answer. Because the most technically challenging and interesting work I've done has been for employers or clients, and under NDA, closed source, and now part of their IP or trade secrets.

Whereas for myself in my own free time I bias more to the ruthlessly pragmatic, which often means the simplest or easiest solution, so I can move on to the next thing.

Random pick from those:

- many many years ago I once wrote a Terminal-like UI widget for Java AWT/Swing apps. This was in the very very early days of Java. To scratch my own itch. It gave me a way in my Swing/AWT desktop apps to embed a console/REPL-like widget (which could be kept invisible/inactive by default, then only appear when a special key pressed) to let me issue CLI-like commands in-app, for example for cheat codes or dev testing or to provide extra features to advanced users. It provided an API for registering comands and their handlers. Had built-in commands like "help" and to repeat the last command, etc. So my Java GUI apps could have the best of both worlds: the "friendliness" of the GUI and the power and conciseness of a terminal workflow. Super simple. Only ever used in a few of my hobby apps (and a few games I considered selling then.)

I named it, originally, in private, SwingShell. Then renamed it to Grio, because that had more personality. (Obligatory Pulp Fiction reference.) I even devised my own little theme song for it. Okay more of a tune. A melodic catchphrase. Why? Here let me show you my nerd license. Hold still, please. This will only take a second.

I created a todo thermal printer so that I can write messages whenever I remember something. For example when I'm lying in bed and I remember that I have to do something or reading a book and think that's a great thought that I should look more into someday.

Basically I have a mobile app that I can send a message to a api. Sometimes it's just a note, sometimes it is a todo item.

Then I have a raspberry pi that polls the api for new messages and prints them onto a receipt/thermal printer on my desk. Then every morning I usually look and see if there is a todo item, or more long term item.

I haven't exactly thought of how to store the messages, but basically when the "receipt" gets to CVS level, I rip it off and store it in in a document shelf organizer. Every few months I'll go through the receipt for any long term touch items.