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

I hobbled together a software implementation of a half-QWERTY keyboard after a serious bike accident which left me unable to type with my left hand for over a month. The hardware solutions were (probably still are?) patented and we’re expensive to my then-very-broke self, so I learned enough ObjC and enough about the underlying keyboard mapping design to ~replicate the functionality in software on my Mac (right hand only until I could start actually using it), and then enough more ObjC to relaunch the thing whenever it crashed (fairly frequently, presumably from memory management issues I wasn’t trying to to deep dive at the time). I really wanted to open source it but it was just a life hack to keep working and I definitely didn’t want to also do a deep dive into the patent litigation risks.

There's a company (Matias?) that makes one-handed keyboards. When I bought one on a lark, 20 years ago, it was maybe $80. I checked back years later and they were $600, and had all sorts of marketing materials about disability accommodations qualification. My guess is that they realized that there was a way to get their product purchased by HR departments, and that such purchasers would be very cost-insensitive. So they 7x'd their price.