Transform an Ikea Side Table into a Music Visualizer

Start with an Ikea Lack table, about $10. The matte white was on sale, so that’s what I used. Draw a square in the center of the tabletop (Figure A) — mine was 16″×16″ (40cm×40cm), giving me room for an 8×8 matrix of 2″ (5cm) square sections.

Carefully cut out the square from the tabletop and set it aside (Figures B and C).

TIP: First drill a hole inside one corner of your square, or make a preliminary cut on your line using a Dremel. Then carefully cut the whole square out with a small handsaw, utility knife, or Dremel.

Remove the corresponding 16″×16″ square of honeycomb cardboard inside the table and discard (Figure D). This will create a space about 1-11/16″ deep for installing the electronics.

You’ll use your tabletop cutout as the mounting board for your LEDs. First, mark the big square off into 64 little 2″ squares, in an 8×8 grid (Figure E).

In each square, mark and drill holes for 2 LEDs: one green, and one red. Put them pretty close together so their colors will blend nicely to amber when they’re both lit. To speed up marking, you can make a little template from a scrap of cardboard or hardboard. I placed green toward the upper left and red toward the lower right (Figures F and G).

Fill the holes with the LEDs — 64 red and 64 green — inserting them from the back so they emerge on the white top (Figures H and I). Take a picture with all the LEDs in place. Feel good about what you’ve done.

You’re just making a very large version of the common cathode matrix shown in the wiring diagram (Figure J). The numbers here indicate which pins you’ll connect to on the Adafruit LED controller board.

First, cut some wires and strip them, lots of them — I suggest you buy a good wire stripper, I did and it made it so much easier! Once you think you’ve got enough, cut some more: You’ll need 56 black, 56 red, and 56 green wires. Each should be about 3″ (7cm–8cm) long (Figure K), but this will vary depending on your array, so just check before you cut all of them.

Next, to save my fat fingers whilst soldering, I twisted the wires into chains of 7 — end to end — so I could solder them easily without trying to hold multiple wires at once (Figure L).

On the back of the LED board, bend the legs of each pair of LEDs so that their cathodes touch, but their anodes are separate. Solder all the cathodes together using the black wires (Figure M), following the wiring diagram.

Solder all the anodes of the red LEDs together using the red wires. Then solder all the anodes of the green LEDs together using the green wires (Figure N). Finally, cut and solder 24 wires, one to the end of each row and column. These will run off-board to connect to the electronics (Adafruit board, breadboard, and Arduino) so their lengths will vary. It’s easiest to locate the electronics near the bottom edge of your LED panel (the front of the table) but you could choose another location, just make sure these off-board wires are long enough to reach.

TIP: You could use red for all the anodes, but we found using red and green here makes the connections a lot easier to follow later. —Jenny Ching, Make: Labs

Connect your newly created LED array to the Adafruit Bicolor LED “backpack” board by soldering its 24 wires directly to the top of the circuit board, following the wire numbering from the LED wiring diagram (Figure J) you used in the previous step. As shown here in Figure O, the backpack board’s pin numbers run clockwise from 1 at top right to 24 at top left.

Now plug the microphone and the LED backpack board into your breadboard and use jumper wires to connect the Arduino as shown in Figures P and Q.

NOTE: I’ve mainly used the circuit diagram from Adafruit, but I’ve made one change: The GND wire from the microphone goes to a different GND connection than the LED array. I found that if I used the same common GND for both, the microphone output was corrupted and the display behaved erratically and didn’t respond to music at all. If you use 2 different GND pins on the Arduino Uno, everything works fine.

Download the Adafruit_LED_Backpack library and put it in your Arduino/libraries folder. Download the project code, and move the ffft folder to your libraries folder too.

Open the sketch Piccolo.pde in the Arduino IDE on your computer, then upload it to your Arduino board. Test the matrix and circuit by playing some music (Figure R). You should see the columns of LEDs jumping and dancing to the sound!

Cut 18 strips of hardboard or cardboard approximately 15½” long and 1⅛” wide. This width is based on the depth of the table, so test-fit your LED panel and electronics into the table before deciding how wide to cut your strips.

On 14 of the strips, use a saw to cut intersection slots every 2″, to half the depth of your strip (Figure S).

For high reflectivity, I used some white laminated hardboard I found in the garage. Then I used the kids’ “gloopy glue” (PVA white glue!) to stick reflective photo paper to the back of the hardboard, and cut it to size with a craft knife once dry. (It’s probably easier to just paint everything white.)

Now assemble the grid and hot-glue the strips in place (Figure T).

Get a piece of plexiglass (perspex) the same size as your matrix. I covered mine in frosted window film, but if you can find translucent or frosted plexi in the first place, it will save you some effort. For added diffusion, I used some baking parchment paper as well.

Cut a little hole in the bottom of the table to allow a USB cable to fit through (Figure U). Hollow out a pocket in the honeycomb cardboard to house your electronics.

Now slide the electronics into place (Figure V). You can leave the microphone inside, or mount it poking out of the table someplace you like. When it’s all aligned to your satisfaction, you can tack the grid down to the LED panel with a few blobs of hot glue (Figure W).

Finally, glue the plastic top in place. I used a hot glue gun, and squeezed a thin bead between the acrylic and the tabletop (Figure X). It’s not substantial, but it keeps everything situated.

Your table is now complete!

You and your Music Visualizer Table are ready to party. Plug its USB cable into a phone charger or any USB port, then crank up the tunes and enjoy watching the giant tricolor pixels dance like splashing fountains of spectrum analyzer goodness!

You can easily program your own custom graphics and animations to run on your LED table anytime — just install Adafruit’s GFX Arduino library.

Before I started this project, I really wanted to build a Tetris table. How would you go about creating something like that?