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

I made a robot location tracking system specifically for use on the carpet at my office.

The carpet was an arrangement of 4 particular colors tiled in squares, so I manually made a carpet map (a few hours in excel!), wrote a carpet color classifier to run from under-robot camera data, then integrated with a particle filter for location tracking. Write up is here:

https://github.com/tim-fan/carpet_localisation/wiki/Carpet-L...

I wrote it only ever expecting usage in this particular office, but if anyone has a similar carpet and a robot that needs localizing, please reach out!

I have a bunch of these. They are my favorite things to make. I've been making things like this for a long time but I only recently started to appreciate them after discovering this article. https://www.robinsloan.com/notes/home-cooked-app/

- I have a disability and require daily personal care so I made a system for recruiting and hiring caregivers. (https://blakewatson.com/journal/a-home-cooked-app-for-hiring...)

- I need to track those caregivers' hours so I can make sure timesheets are accurate, and I wanted to do it with minimal effort. So I created a plain text syntax readable by a web app I created that takes that syntax and outputs exactly what should go on the timesheets.

- Sometimes the government agency that runs the program doesn't send me enough timesheets, so I created a "forgery" of their timesheets in CSS where all of the values are interchangeable via JavaScript. Now I can print any timesheet for any one of my caregivers for any time period on demand.

- I made my own web-based bookmarking tool to replace my Pinboard account. It automatically sends every bookmark to the Wayback Machine. (I wrote about that one and a couple of others https://blakewatson.com/journal/the-joys-of-home-cooked-apps...)

- Sadly I'm no longer able to use this one because of decreasing strength, but I once created a custom mobile-based keyboard for typing on my Mac. https://www.youtube.com/watch?v=Pre6EQGIuKY

- I wanted to be able to share my plain text notes so I made a CLI for selectively publishing notes to the web.

Really most everything I make outside of my day job is for me/family initially, but a lot of it I end up publishing. For example my main side project is A Fine Start (https://afinestart.me/). It actually started as an assistive technology just for me—typing is difficult so I wanted a new tab page with just clickable text links. I used it for a while myself before eventually turning it into a browser extension and service for other people.

My brother and I built a mini webapp that takes data from the Strong app for workouts, and shows you a list of all your muscle groups and filters it with color based on how much fatigue each muscle has accrued over the week. It also gives you recommendations of how much weight you should lift for your next workout. It's a nice way to make sure each muscle group is getting exercised enough each week!

A little buzzer/led you can plug into an épée to detect hits without a scoring box, there's no grounding so it still triggers on hitting the opponents weapon but was more than good enough for practices.

It was very simple, using a 555 timer and took almost no time to make, but it was among the best returns of effort I put in vs value I got out of it. It also stands out as one of my few personal projects that was something physical since most of them are only software now, and more tools than things purely for fun.

I've been working on https://instellar.app. It's a SaaS product that will enable anyone to turn their own infrastructure into a PaaS without needing to hire a DevOps.

I did this because I've had problems hiring DevOps (lack of resource / lack of people to hire / and kubernetes was just too complex). I decided that I need a tool let's me have my own heroku on my own infra and here we are.