When I left the Android ecosystem, I left an app behind: FareBot; this left me without a means to read the NFC transit payment system used in the Seattle metro area. To remedy this, I decided: I'm going to write my own fare card reader. Now, ZaibatsuPass is getting close to releasing on the Microsoft store for the rest of the world to use.
Desperate times calls for desperate measures. When you need a blue box, you need it now. Unfortunately, when I needed this app the most, It wasn't availalble. MF and DTMF tones are still useful today as a means of controlling remote devices (amateur radio equipment, especially).
Back when I used Android, I forked yaaic to add some features I felt were missing. These features included SSL certificate checking, themes, etc. I may occasionally work on it, but development has otherwise halted.
Why do I build open source software for Windows?
I get asked this on occasion. There's a thing going around in the Open Source community that says that it's bad to develop open source software for Windows. I personally think this mentality is corrosive to the fundamental ideology of software development and the hacker ethic. When we built software for UNIX, we built software on top of the de facto non-free system. It wasn't until projects like the BSD distribution slowly eroded away everything that AT&T had built that we began to have a "Free" world.
Free software shouldn't be an exclusive clique. It should be available to all who want to use it; this is why I write software for Windows.