Yes! My last hobby project (I explicitly point out "hobby" project instead of "side revenue", but the article mentions "hobby" in the first sentence as well) wa

Yes! My last hobby project (I explicitly point out "hobby" project instead of "side revenue", but the article mentions "hobby" in the first sentence as well) was exactly that. Because it was a hobby project, I went completely mad on it. I built my own SPDIF interface, from scratch, using an FPGA. I let the hardware broadcast the sound frames over Ethernet. I also re-implemented Sony's proprietary consumer electronics control protocol, in hardware as well (a microcontroller could have easily done that instead). I greatly overengineered a circuit board, despite having a functional "test setup" already that did the job more than well enough. I wrote largely unnecessary client software, using language extensions I've never used before. The task at hand could have been solved with buying a cheap USB sound adapter from eBay and some manual work instead. Had I gone down that route, I probably would have completed the task in a fraction of the time that building this project took. But I had so much fun along the way and learned so much about electronics, FPGAs, SoCs, static typing for python etc., all because it was a project for me and nobody else. One big lesson I've learned, though, is that having an actual task you want to solve greatly helps you in finishing your project. I ran out of steam a number of times and the project fell to the wayside, but because the underlying task was not fulfilled yet, I always went back to it and quickly got completely focused on it again. Projects that I only did for playing around and learning most often got abandoned.