I made a clock based on an IV-18 vacuum florescent display tube. In the process I learned CAD, CNC, aluminum anodizing, metal turning, SMT soldering, laser cutting, box making, power supply design, and a dozen other skills I use every day today.
I built a total of five of them. I sent one to the person who designed the enclosure, one to my brother, one to a friend, one to eBay for sale (which ended up in Germany), and kept one for myself. It still sits on my desk ticking along quite happily. I've changed the backup battery once in 14 years and have made little tweaks to the firmware over the years.
Here's the clock's homepage, which has some pictures: https://vonnieda.org/tc18, and more pictures on Flickr: https://www.flickr.com/photos/vonnieda/sets/7215762293577593...
And a blog post that goes into excruciating detail about the entire process: https://vonnieda.org/archives/1406
I built a total of five of them. I sent one to the person who designed the enclosure, one to my brother, one to a friend, one to eBay for sale (which ended up in Germany), and kept one for myself. It still sits on my desk ticking along quite happily. I've changed the backup battery once in 14 years and have made little tweaks to the firmware over the years.