When starting this project I naturally took a look at some of the ones time circuits displays that were previously made by others. They all looked awesome! However, all but one I found (I'll explain this later), had one thing in common - the month displays looked weird.
When you compare the segment displays that are available in real life, and then look at the TDC in Back to the Future, the real displays were spaced way too far apart. After some more research, I realized that it was not only the spacing that was off, but in the movie, they didn't even use segment displays - they used gels cut to look like displays, then put incandescent bulbs behind them. This is also why some of the characters (like the N & D) in the movie displays aren't even possible with actual 14 or 16 segment displays.
This image is all the months that appear on the TCD in BTTF compiled by Parts Not Included, who posted their own TCD project with excellent documentation in 2017...
After even more research I found that NO ONE makes a 3 character 14 segment display with the spacing that close together. There are some manufacturers that have a 2 character, but they are still far apart.
As much as I wanted what was available to work, I couldn't bring myself to make a replica with such a glaring flaw. I decided to have the segment displays custom made with the correct spacing, size, and even pitch. This is not something you just casually decide to do, and I understand why others haven't done it. It's expensive, and you have to order a LOT of them. I went into this hoping that others would appreciate the accuracy as well.
More coming soon!