Reusing some left over spy mirror acrylics (because we didn't want to throw away stuff) and experimenting with UV light. While the big led cubes can be scaled up easily, for smaller cubes using LED stripes become to complicated and take to much space. Therefore we needed another light source for the columns. Thats why i exchanged the active stripes with the passive fluorescent material, enlightened by a single LED. As a result, infinity earrings were born (just by chance happening at valentines day :).

Since they are easy to make, can reuse left over material and use few different construction techniques as well as electronics, they might be a also a nice idea for children workshops (or even easier/faster: just one micro cube on a small podest similar like the big one in an instructable before)

For each mini cube we need a little bit of spy mirror (lasercut into 6 27*27 square millimiter pieces), a 3D printed frame for both mirrors and batteries (2 2032 3V coin cells), a 5mm UV diode and fluorescent paint. A premade ear ring hook and a small piece of silver wire to attach it to the battery holder is also needed.

Step 1: 3D Printing and Painting

After laser cutting the mirrors (mirror.svg - ok, lasercutting because we can, since only rectangles are necessary any cutting/sawing would be fine) the two designs for mirror and battery holder are printed (cubeEarrings.scad). With a Prusa i3 MK2 i already achieved a press-fit connection by just using the right distances.

Afterwards, the necessary support structure is removed and especially the cube frame addidionally smoothed with a hot plate tool by melting the surface (just because i wanted to test that tool, not really becessary). The inner frame (see picture) is painted with white uv-fluorescent paint (2 Layers), maybe directly printing with uv-reactive filament would be another option.

The mirrors are the plugged into each side. Since the UV diode (hole on one corner of the cube, again just pressfit) reaches slightly into the mirror area, 3 mirrors are beveled at one corner with a file.

Afterwards, assembly of the battery pack can begin.

Step 2: Battery Holder

For Power supply the two coin cells are stacked into the holder one after each other (make sure not to break it), to supply up to 6V (the necessary voltage of the UV-diode exceeds the voltage of just battery, while the 20mA delivered by the two batteries in a row are still low enough to not damage the LED).

The ear ring hook is attached with a small strip of silver wire on one side of the holder. (Just wrapped around and twisted).

Step 3: Power On

Both wires of the led are then put into the tiny holes of the battery pack and make contact with each battery pole. It might be necessary to bend them a bit for good and reliable contact, and at the moment they are just hold together with press-fit again.

For more lively usage, it might be necessary to secure both the LED legs on the battery holder with a drop aof glue, as well glue the mirrors on the frame, but at the moment they hold good enough together this way.

Enjoy!