Uranium glass always fascinated me and after finding out you can just buy uranium glass marbles online for like $15 I quickly found myself with some. I wanted to display them properly, and as uranium glass fluoresces under UV light, I decided to build a simple stand to illuminate them.

I designed this around putting 3 marbles in a glass dome for aesthetics with an Arduino nano handling the power and on/off functionality. There is a button that currently switches the power on/off so it can stay plugged in without being on all the time. I wired the 3 LED's to digital, PWM-capable pins, so 

BOM:

3x Uranium glass marbles: https://unitednuclear.com/misc-nuclear-items-c-2_8/radioactive-uranium-doped-marbles-small-p-1143.html

1x Arduino Nano

3x 100ohm resistors

1x SPST button: https://www.amazon.com/dp/B07X8S99RH?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_5&th=1

3x 5mm UV(ish) LED's: https://www.amazon.com/dp/B077X8P33G?ref=ppx_yo2ov_dt_b_fed_asin_title

3x M3 screws

1x Glass Dome: These are surprisingly hard to find, and the one i bought from Hobby Lobby isn't up anymore. Mine is 80mm OD.

Wiring:

Pin numbers match the code. D9,D10,D11 are PWM pins so with clever coding some dimming or other effects are possible. When (if) I get around to it I'll post it here.

Code:

//Cross_engineering 6/14/25 #include const int LEDshort = 9; const int LEDmid = 10; const int LEDtall = 11; Button button1(2); bool state = 0; void setup() { pinMode(LEDshort, OUTPUT); pinMode(LEDmid, OUTPUT); pinMode(LEDtall, OUTPUT); button1.begin(); } void loop() { if (button1.pressed()){ if(state == 0){ digitalWrite(LEDshort, HIGH); digitalWrite(LEDmid, HIGH); digitalWrite(LEDtall, HIGH); state = 1; } else{ digitalWrite(LEDshort, LOW); digitalWrite(LEDmid, LOW); digitalWrite(LEDtall, LOW); state = 0; } } }

You need to have the Button library installed

The code is very simple and just toggles the LED's on and off with each button press.

Prints:

PLA should work though PETG is more UV resistant, though I have no idea if this exposure is enough to even matter.

 

P.S. Uranium glass is completely safe. It stopped being made because uranium became harder to get, not because they were hurting people.