Introduction: How to Assemble 3D Light Cube Kit 8x8x8 Blue LED MP3 Music Spectrum From

This is what we're building:

3D Light Cube Kit 8x8x8 Blue LED MP3 Music Spectrum

Optional Transparent Acrylic Board Housing

If you like this LED cube, you might want to hop on my YouTube channel where I make LED cubes, robots, IoT, 3D printing, and more.

Step 1: What's in the Kit

  • Pre-soldered PCB Base
  • Wireless remote control
  • Cables: USB, Audio
  • USB to serial interface to program the cube
  • Wires: Hookup wire, jumper wire
  • Female headers
  • Screws and standoffs
  • LEDs

Step 2: Tools

This kit requires soldering over 500 LEDs. Make sure you have a good soldering iron or you will have a bad day.

  • Good quality soldering iron - I had mine set to 325 Celsius
  • 0.032" diameter 60/40 (leaded) solder
  • Wet sponge or brass ball to clean iron tip
  • Right angle ruler
  • Small pair of pliers
  • Flush cutters
  • Phillips Screwdriver
  • Flux pen (optional)

Step 3: Test the LEDs

Replacing a broken LED buried within the cube would be very difficult, so I always check all the LEDs before and after I solder them. To do this you will need:

  • 5V supply (wall adaptor, power bank, or Arduino)
  • One resistor (anything between 470 ohm to 1K ohms will work)
  • Breadboard
  • Short jumper wires
  • Two longer wires to test soldered LEDs

Plug the long (positive/anode) lead of the LED to +5V and the short (negative/cathode) lead to ground.

Use two clearly labeled containers to keep the tested and untested LEDs separate. Tested and untested LEDs look exactly the same :-)

Step 4: Jig to Build an 8 X 8 LED Wall

The LEDs in this kit are pointed forward towards the viewer rather than up towards the ceiling. By clever bending of the LED leads, the cube is put together without needing extra wires.

The jig will help us build the cube one vertical wall at a time, and then we will connect the walls together.

To prevent the LEDs from popping out while we solder them in the jig, install the provided standoffs.

Step 5: Bend the LED Leads

How to hold the LED

  1. Hold the LED with your left hand.
  2. The shorter (negative/cathode) lead is on the right, the longer (positive/anode) lead is on the left.

How to bend the short lead

  1. Using your fingers, bend the shorter leg towards you. Flush with the base of the LED.
  2. The bent lead should be parallel with the flat side of the LED.

How to bend the long lead

  1. Note the bumps on the leads.
  2. Using pliers, bend the longer (positive/anode) lead to the left.
  3. It is very important that this lead is NOT bent flush with the LED so we would not shortcircuit the positive and negative leads when we solder them into a grid.


The kit contains extra LEDs. We "only" need 448 LEDs bent as described above and 64 LEDs with the longer lead NOT bent!

These 64 unbent positive leads connect each wall to the wall behind it forming the cube.

Step 6: Soldering the LEDs


The "cube" is taller than wide. When putting the LEDs into the jig, the negative leads (bent flush with LED) should point down towards the PCB. The positive leads should point left, and the leftmost eight LEDs should have the positive leads not bent.

Soldering tips

Set the soldering iron temperature to about 325 degrees. Keep the iron tip clean by regularly wiping it on the sponge. Bring the tip close to what you're soldering, put a little solder on the tip so when you touch the leads to be soldered it would make good heat contact. Add a little more solder, remove the iron. Avoid movements until the solder sets.

Shiny solder surface indicates good solder joint. If you see a matte finish joint, reheat it and do not move until the solder sets.

If you still have trouble soldering, consider getting a flux pen. Solder will stick to wherever you apply flux to.

Retest the LEDs

Before you remove the soldered LEDs from the jig, re-test all the LEDs again. It would be easier to remove an LED and replace it at this point compared to after you remove the wall from the jig. Remember to test with a current limiting resistor or you risk burning the LEDs! Clip negative to one of the bottom negative lead, and test each positive layer, go to the next negative lead, repeat.

Step 7: Install Sockets

Separate the provided header pins into individual pins using the flush cutter.

Solder them onto the PCB. We will insert the soldered cube walls onto these headers.

Some of the header pins are obscured by the speaker. Unscrew the speakers temporarily while soldering those pins.

Step 8: Install LED Walls Onto the PCB Base

Use the 90 degree steel square to ensure that the LED wall is plugged in and soldered perfectly straight up in all directions.

I used a foam core as a jig to keep the distance between the walls consistent (20mm).

After inserting a wall onto the base. Solder it to the wall in front of it. Each horizontal layer will share common positive. Make sure that none of the vertical negative columns touches the horizontal positive layers.
Once you're done with all eight walls, use the provided thin white wire to power the horizontal layers. H1 should power the bottom-most layer, H2, the second layer above it, all the way to H8 powering the topmost layer.

Optionally, you could add an extra wire on the top left side to stabilize the cube. IMPORTANT: Make sure you join the positive leads and not the negative leads.

Step 9: The Enclosure

The optional plastic enclosure is self explanatory. Carefully peel off the protective paper and assemble the enclosure using the provided machine screws. Using magnet(s) to hold the nut in place during assembly worked well for me.

Step 10: All Done!

Enjoy your new cube!