RGB Infinity Cube

by Zachary Goode in Circuits > LEDs

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RGB Infinity Cube

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RGB Infinity Cube

This project was inspired by an art piece I saw while browsing various build websites. I had seen plenty of infinity mirrors before, but this one was different; it utilized RGB LEDs instead of the typical single-color ones. I had experience in constructing light boxes, again out of single-color LEDs, but I was confident that I could adapt both RGB and an infinity mirror into my build.

As my first Instructable post, I am entirely welcome to questions, concerns, or clarifications. Criticism of the helpful variety is encouraged.

I want to start this by saying this is a difficult build. If you don't have patience and get frustrated easily, proceed cautiously. The hardest part of the build is the woodworking portion; the electronics are relatively easy to assemble.

Materials & Tools

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Materials Required:

*Electronics

  • RGB LED strip; 5V 144 LED/Meter

-I bought 4 meters so that I would have some extra and ended up only using 3 meters

  • Arduino Pro Micro; the ATMEGA328P 5V variant

-This is overkill as only one pin is needed and the program is small, but it is a cheap and small form factor option

  • 5V Power supply with enough amperage for the LED's used

-I chose a 8 amp one. A wall wart type is preferable

  • Misc. Stranded Wire

-I recommend at least 16-18 awg for safety with the amount of current the LED's draw

  • On/Off switch

-To turn the cube on and off (Duh!)

  • Push button with LED

-To change the light pattern playing

  • 10K Ohm resistor
  • 1000uF 25v polarized capacitor

*Other

  • 1/2" thick wood planks

-I used walnut since I like darker woods; they contrast with lights better. I also recommend buying the finished planks at Home Depot or Lowes if you don't have a planer or joiner. While more expensive, these boards are very convenient.

  • Wood Glue
  • Super Glue
  • Two part epoxy
  • Sheet Glass; .125" thick

-Windows glass should be good enough and is fairly cheap

  • Oil or lacquer for finishing off the wood

-I prefer to use Danish oil on walnut, it brings out the contrast in the grain

  • Clear PLA filament 1.75mm or 3mm, whatever your printer uses
  • Window tint film
  • Heat shrink tubing

Tools Required:

  • Soldering Iron
  • 60/40 Flux Core Lead Solder
  • Utility knife
  • Glass Cutter
  • Table Saw
  • Miter Saw
  • Drill and appropriate sized bits
  • Sander with assorted grits from 180 up to around 400
  • Vinyl applicator tools (squeegee, knife, squirt bottle, paper towels)
  • Wire cutters
  • Pliers
  • Wire Strippers (optional, but makes things easier)
  • Hot glue gun
  • FTDI programmer board
  • Mini USB cable for the FTDI
  • 3D printer (optional but makes some parts easier to make)

Building the Frame

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The first part in the step is cutting the wood to shape. In this case since we are using a triple miter joint to hold it together we need to cut the wood into a trapezoidal shape the exact dimensions and angle are in the SolidWorks drawing up above. Now keep in mind that the length of the pieces doesn't matter it's the angle of the miter cuts.

Make these cuts in order:

-Cut the planks to 3/2" wide and about 9"-10" long

-you'll need 24 of these pieces

-On the two ends of each piece cut them to a 45 degree angle using a miter saw as shown in the drawing up above

-Using the table saw again cut a .125" dado along the narrow side of the pieces to create a notch to set the glass sheet into

-Now make an 45 degree angled cut along the wider edge so that the mitered corners fit together

-Also cut some wider planks into sections to make a base for the cube to rest on as shown in the pictures above, you will need three of these pieces. This is where the control electronics will be housed.

Rough sand the wood before fitting to make sure that all of the edges being glued together are flat.

Start to fit and glue the pieces together to make the three way miter as shown in the image. Drill a hole in one of the corners of the cube to route all of the wires to the base, preferably the worst looking corner so it is hidden.

Make the Base for the Cube

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Taking a wider piece of walnut cut out three trapezoidal pieces. On the miter saw and/or table saw cut a 45 degree chamfer along all the edges. I ended up using both the miter and table saw for this.

Drill any necessary holes for the power jack, switch, and button. After drilling the holes, glue the pieces together.

Complete the Frame

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Take the main part of the cube and the base and glue them together to make make one solid piece. Have the corner of the cube with the hole in it be the one glued into the base, as this is where all the electronics go.

After everything is glued together and solidly attached now it is time to finish the frame so that the electronics can be prepared and added. Sand everything until satisfied with the texture and look. I went from 150 grit all the way up to 400, using a mouse sander for most of it and getting the hard to reach parts by hand. When done sanding apply oil, in my case danish oil, with a brush and then wipe off excess with a towel. One or two coats of this should be more than enough. Again, wipe off all excess oil.

3D Print the Parts to Hold the LED's and Install Them

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3D print 12 of the wedges to mount the LED's on in each of the edges of the cube. Cut the LED strips to size (in my case 31 LED's each) and then tape them into place using the adhesive on the back of the strips. Super glue these pieces into the cube, one at each edge.

I'm going to be honest here. Soldering the LED's together was really, really difficult. I definitely misjudged how hard it was going to be to get the wires in with the limited space available. It worked in the end but it took several hours to get the strips installed and then working. This step definitely takes some patience. I ended up breaking one of my strips so make sure to have some extra on hand in case that happens to you. Connect the strips together using jumper wire so that there are three different sections of four edges. These three sections are each going to connect to a different pin on the Arduino Pro Mini.

Downloads

Preparing the Glass Sheet

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Cut 6 glass pieces to a little larger on each side than the shorter of the edges on the pieces of wood

Practice cutting. It is harder than I thought it wood be. The first picture up above is examples of what happens when you don't know what you are doing. Once you get the hang of it though it is fairly easy to do. Getting the technique down just takes a little practice

!!!WHEN CUTTING GLASS WEAR SAFETY GLASSES AND GLOVES. THE EDGES CAN BE VERY SHARP!!!

In my case this ended up being about 8.25" by 8.25" since my shorter edge measured about 8"

Sand the edges of the glass to get rid of any shards and to smooth out the sides

Put window tint on one side of the glass according to the instructions for your particular tint and trim off the excess

For my window tint I used a spray bottle to spritz water on the adhesive side of the sheet and on the glass and then put the sheet onto the glass. Using the squeegee squeeze out any bubbles and water, let it dry, and trim the edges

!!!MAKE SURE TO SQUEEZE OUT ANY AIR BUBBLES WHEN APPLYING!!!

Attach the mirrors to the frame with the film facing inward with a two part epoxy. Feel free to be generous with the epoxy, more is better, but don't use so much that it gets all over the mirror surface.

After the mirrors are attached and the epoxy is dry, super glue the cover pieces over the led's. you'll need to print 12 of these, one for each edge (optional step; not necessary. just makes it look better)

Downloads

Program the Arduino

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Open the Arduino IDE and open the code in the included file. Make sure that the Arduino Pro Micro 5V 16Mhz is selected and plug the Arduino in using a programmer as shown in the diagram. I used an FTDI programmer. Plug it in as shown above. Press the upload button and voila, the code has been uploaded.

As of right now I only have one program as the code proved troublesome to get working. I will be updating it later and adding more patterns in.

Downloads

Assemble the Electronics

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Now to connect all of the electrical parts together. This means mounting the LED strips inside the cube, mounting the button, adding a power jack, and connecting it all together. If you follow the diagrams up above it should all work out just find. Before powering anything make sure that everything is supplied with adequate power at 5V (this means use thick enough wire to handle the current of the LED's).

Save the JST connectors on the ends of the LED strips that were cut up to put on the cube. These make it much easier to connect everything during assembly.

The capacitor used is a 1000 uF 25V polarized cap. It's not necessary, but is recommended to smooth out current spikes.

The resistor used on the button is 10K ohms and is to hold the pin to ground when the button is not pushed so as the pin isn't "floating." This is a necessary component For the button and the dc jack put them in the base before soldering them so that the wires can be hidden in the base.

You Are Done

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Enjoy the work of art that you have created and confuse your friends with the optical illusion of the infinity mirrors!