I've had to do a lot of my homework at night recently due to my work shifts ending very late, and since it's difficult to see the calculator keys in the dark I've been looking at ways to make them more visible. The closest solution I've seen to this is a post awhile back asking if anyone's been able to backlight the keys, but I haven't seen any updates so I thought I might just try something simplier like painting glow-in-the-dark keys.

Anyway, this is a very long way of saying that somewhere along this process I decided that I want to try to make completely new keys so that it's easier to paint them.


First, I took apart my old calculator (the blue one) because it has water damage and hasn't worked in a year, as practice to make sure that I actually could take a calculator apart so that I wouldn't physically break my current one (which I took apart earlier today, I'm currently waiting on my test keys to finish printing, so when they're done I can make sure they fit, and also that the text is legible).


Here's all the measurements I jotted down for the 6 different types of keys on the 84 plus CE, including the bottom cavities on all of them with the little spike-thingys (not sure what to call them).


These are the sketches I made in Shapr3D following the measurements.


Sketched out the text, then engraved them on the models.


This is what all the keys look like underneath.

Currently, I'm waiting on my test prints to finish. I have a resin 3D printer that I've been able to make detailed miniatures with, so I'm hoping the small text won't be an issue. I'm not sure how well these would print on a filament printer, but if anyone would like to try let me know and I can add the stl files here later.

If the prints turn out well, then I plan to get some acrylic glow-in-the-dark paint and dilute it for my airbrush. Since the text is engraved, I'm hoping that I can paint the actual body of each of the keys without the paint getting on the letters.

I'll update with progress photos asap!

(Also, apologies if this is a project that has already been done, like I said before I haven't seen any posts regarding solutions to making the calculator keys more visible, but let me know if there are or if there's another corner of the internet that I haven't seen with information like this and I'll definitely check it out!)

(edit: Sorry that the photos weren't showing, I wasn't adding the link properly but it should work now!)

This looks great so far!

I did backlight the keys with LEDs a while ago in this topic: https://www.cemetech.net/forum/viewtopic.php?p=296907#296907
However, it was such a tedious process I even mentioned in the post:


I'm super interested to see how this turns out. Could you please share the 3D files? I'd love to do this to my other calculators!

I was wondering if anyone had been able to use LEDs as backlights, so thanks for sharing your post! Even though you said it took you quite awhile, the result is very impressive! I might do it someday in the future, I'll have to get more practice in modifying calculators though, I'm still very new to all of this. Which is why I wanted to try just 3D printing some new keys and using glow-in-the-dark paint instead, it seems like a much less intimidating task 😅

Anyway, here are the files: https://github.com/beetletrees/ti84-keys
I added the stl with all the engraved keys, but I also added a file with just the 7 different key shapes in case you want to customize them yourself.

I'm going to be busy for the next couple of weeks, so I won't be able to post an update soon, but my plan is that I'll be able to finishing printing all the keys by tomorrow so that they'll be ready to paint when I get back. I just ordered a couple supplies that will be delivered while I'm gone, so I'll have everything that I need.

From my own experience, most glow-in-the-dark paints don't last very long because it's manufactured with the idea that customers shouldn't have to make the paint glow and that it should already have that quality since that's how it's advertised. A lot of people don't want to or don't realize you have to charge the substance so that it can actually glow.

Basically, to get a material that will actually function well so that I can see the letters and numbers on the calculator keys in the dark, I've decided to just make my own. I ordered some strontium aluminate glow-in-the-dark powder, which (with a UV light at least) you only need to charge for a few minutes to get around 12 hours of a really bright glow, which is more than enough time I need for a late-night homework session. I won't be mixing the powder with my acrylic paint, according to google most water-based substances break down the chemical bonds that allow the powder to be activated so that it can actually glow, and will make the end result not very visible. I still have a good amount of clear epoxy resin from a few years ago when I used it in my crafts a lot, and apparently is perfect for the powder.

I haven't ever made my own glow-in-the-dark substance, so I'm hoping it will turn out well. I hope to post updates by the end of this month though!

*bump* Have you had any success with the glow in the dark powder?

This looks really cool! I'm going to try printing out some of my own on my filament printer and see how it goes.

oh that's cool.
I actually mounted a mirror on top of my calculator so it reflects this light from the screen maybe this would be less crummy.