I built a head tracking mouse replacement. It’s assistive tech for people with paralysis, bad RSI, etc. The software is fairly polished with a decent GUI. I used OpenCV and NumPy for the visual processing. Aspects of it were based on a good technical paper Microsoft put out on mouse ballistics. There are some commercial products that do the same thing, but at least compared to the ones I’ve tried, mine is more precise, and much less susceptible to background noise. The latter ends up being pretty important for long term usability. I built it to be cross-platform, Windows, Mac, and Linux. I’ve used it every work day for the past 8 years; it totally cured a bad case of RSI I was having; for that alone I have to consider it a total success.<p>I chose to open source it because I decided ultimately it was way more of a niche business than I wanted to be in, and I wasn’t convinced it was a money maker. I figured maybe I could help some people who needed it.<p>I presented it at a major hacker conference; the same year Edward Snowden was the keynote, that was very cool. So what happened after that? I think it went from having 1 to 4 stars on Github (and zero forks). I’ve never heard of anyone using it. It’s there if anyone wants it. How do I maintain it? If I find a bug that bothers me enough, or an OS compatibility issue comes up, I fix it. These days I only really maintain compatibility with Linux and only a dedicated hardware mode, that uses an Arduino to get foot pedal inputs for mouse clicks.<p>This can’t be an uncommon scenario, you make something cool, release it, and all you hear is crickets. The software was always single-purpose: a tool for me to do my work. Without being hyperbolic I can say it literally saved my career. One other unexpected side effect: any job interview in which I’ve gotten far enough to talk about this project I’ve gotten an offer. I don’t think the code is that amazingly clean and it’s not solving an impossibly difficult problem, but there’s something to be said for making stuff that actually works and having the entire code base visible for review.