This is an old video I made as a quick showcase some time ago and will be replaced with another better one soon:
Even this LED cube is much much easier to assemble than my previous “Geodesic(k) RGB LED Spheres” , it still requires quite some experience, basic knowledge in electronics and a good amount of patience.
I will e.g. not provide an exact electronics schematic because it's quite individual. But if you're familiar with WLED, which I use to run it, you will be able to do it.
Please read all the instructions below carefully before starting.
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I highly recommend to print it in PETG. It can get quite warm and PLA will get soft at temperatures >45-50°C.
Print the first two layers in white (get the whites white you can find) and the following layers in a reflective but not translucent color like silver or “metal like” filament. I tried many different ones to find the best one (Extrudr metallic PETG).
Summary:
You need these additional parts:
Tools:
Battery
Basically you can use whatever you want and like the most.
The insert provided is made for a 3s1p configuration which allows the fast charging time.
I don't use any spacial self-programmed software for the cube, but just WLED out of the box. This worked so much better than I expected first, that I never had the need to create my own code.
Install WLED as described on their site.
You will need a good strong glue to assemble the side and bottom parts. I highly recommend to use an epoxy with long enough work time (>15 min.), because you will need some time to get all parts together and align them properly. The one I used is “UHU Plus Endfest 90” (Epoxy Ultra Strong):
It's recommended to (wet) sand the sides a little bit to get rid of any bumps so the parts fit together more nicely. To keep the 45° angle a bit easier, which is very important, you can use the sanding jig you'll find in the files section.
Glue in a short piece of filament to these five holes (one side & bottom) using a drop of super glue on each side part. They are used to align the parts properly. It's easier if you glue in a longer piece and cut it to length:
NOTE: The top side is the one with the slots for the magnets!
Test that everything fits together nicely (no gaps) and none of the filament pieces from the last step are too long (they have to be quite short):
To protect the surfaces I covered them with tape:
Tape together the four side pieces edge on edge:
Now it's time to apply the epoxy to the side faces (only the sides, NOT top/bottom). Don't add too much epoxy to prevent it from squeezing out too much:
“Fold” the sides together and fix it with some tape:
Now add epoxy to the bottom faces and fixate it with some more tape:
Let the epoxy harden out properly before removing the tape.
I then used the round metal of a screw driver to smooth out the edges, which turned out better than I expected tbh.:
Solder together the panels in the order below worked best for me.
It's important to keep the cables between the panels as short as possible, except for the top panel which is used to open the cube later. There is not much space to waste within the cube.
Before starting to solder, mark each panel with its order in the chain (1-6) and which the bottom an top edge is (only barely visible on the photo). This makes it a bit easier to keep them the correct way.
I connected the power in the middle to have less voltage drop,
Don't insert them into the cube yet, except you want to test it already. They will be hold in place with the “insert” part which holds the battery and electronics (no glue required).
As mentioned already, I will not provide an exact schematic how to wire everything. My solution is not perfect and I'm not super happy the way it's done at the moment (but it works).
Basically you have the power side, 18650 battery cells in 3s1p configuration connected to a BMS. This goes to the switch and then to the Step-Down converter (an UBEC with 5A worked best for me and used up the least space). It also needs some connectors to charge and balance the cells with an external charger. Finally the output of the UBEC goes to the VIN of the ESP32 and the LEDs.
For the logic side you'll need a level converter if the used microcontroller outputs 3.3V, which is the case for most of them. I can work without it, but will be definitely be more stable when using one. The pin used to control the LEDs, normally D2 on a ESP32 when using it together with WLED is connected to the level converter and the HV side goes to the DIN of the first panel.
Than can look more ore less like this at the end. Be careful that everything fits into the “insert” part:
The connector for the cell balancing will be either connected to the BMS or external charger. My external charging bypasses the BMS.
Slide the battery and electronics pack into the insert part:
It should not fall out if you turn it upside down. If it does, fix it somehow.
Put 12 pairs of magnets side by side and mark the upper side of each pair:
Slide each of the unmarked magnet into a slot of the side parts and fixate it with the marked magnet so they don't fall out until the matrix panels are installed in the next step. The magnets are not super strong, so you can also use a piece of tape to hold the marked magnets.
Now install the prepared panels. No glue required. They will be hold in place by the insert.
Also make sure all cables run along the sides, as the insert must touch the bottom panel.
Slide in the insert:
Add some hot glue to the holes in the insert to prevent the insert from falling out when turned upside down. This way you can remove the hot glue again in case you have to replace a panel for example.
Take each single marked magnet and insert it into the corresponding slot of the top part. Take care to insert it in the correct way so they are attracted to the ones in the side panels.
To fix the top panel you have to use some drops of super glue.
Shorten the three wires from the panels and solder on the plug (or you can solder it together without a plug if you want):
Now put on the top part and make sure the magnets hold it in place. As mentioned already, these small magnets are not very strong, but for me it works perfectly fine.
There are also holes for small pieces of filament on the top of the side panels and the top panel itself. These can be used to prevent the top panel from sliding which should make the magnets hold it better.
Now it's time to turn it on. If no “magic smoke” raises up, connect to WLED and start playing around.
The author marked this model as their own original creation.