What is SpaceFN and why you should give it a try
The SpaceFN concept - setting up your space key as a layer switch when held - is probably one of the most useful tweaks in the keyboard hobby. Let me explain how it works. My SpaceFN article on kbd.news made some rounds recently - quite surprisingly given the age of this concept. This piece you're reading is a condensed version of the full post. If you're left with unanswered questions, you'll most likely find the info you're looking for in the original write-up. On my imaginary top list of the most useful keyboard features, tweaks and hacks, SpaceFN would deserve a podium finish for sure. But what makes it so special? In short: SpaceFN is easy to implement, easy to learn, costs nothing, can be used with any keyboard, and can improve your productivity instantly. I will list its benefits below, but can state right at this point that the SpaceFN concept, setting up your space key as a layer switch when held, is clearly one of the most useful tweaks in the keyboard hobby....
Apr 30, 2024
A better bet would be to build a board traditional through-switch LEDs and just using some UV LEDs from amazon etc in my opinion.
The easy/traditional way would be to use through-switch LEDs like these:
Using 2x3x4 square UV LEDs like these: https://www.amazon.com/dp/B071HWPTND/ref=cm_sw_r_cp_apa_p63tAb0PE8EAT
You can read more about using LEDs with Cherry type switchs here (also where I got the pics from):
https://geekhack.org/index.php?topic=54702.0
Past that I'd probably just use some glow in the dark/UV reactive paint to get the effect you want. Removing PCB mounted RGB LEDs, replacing them with UV LEDs, and working tritium tubes into the actual keycaps really complicates things and likely won't work out well.
https://www.reddit.com/r/MechanicalKeyboards/comments/64d7uu/leds_and_cherry_profile_keycaps/