Introduction: Digital Disco Ball

**Please note that I am still fine tuning this tutorial, and trying to add some more detail.

This is a project I created for a class. We were required to design an object for a particular space. The object had to exhibit some kind of memory which affected the behavior of the people in that space.

During the period when I was doing research for this project, I happened to be walking down the street one night and passed a bar with a live jazz band playing. I went in to listen for a while and was inspired by the connection between the audience and performers. The audience stood and watched, some bobbing their heads or tapping their fee, others danced on a little dance floor, while the band acted as the catalyst controlling all of this behavior. Watching the dancers was a lot of fun and made me want to do it myself, although I didn't because they were much better than me. I got to thinking about how dancing has an unique way of lifting peoples spirits. All the people I watched appeared to be having a lot of fun! Why is it that people can't help but be happy when they dance? And what about it is so infectious? I also like the fact that dancing is also such an inherently social activity which motivates different people to interact with each other.

I thought a disco ball would encapsulate this kind of environment and behavior very well. The concept is that when people stand in one position on the dance floor, a shadow from the disco ball is cast behind them. After, I wanted to retain their shadow in the same place even after they walk away. The longer they stood there, the darker and more pronounced the shadow they left behind. Conversely, when people move and dance more actively, I wanted to brighten the lights in that area to highlight them and motivate movement and dancing behavior. There are actually many more things that I can program the disco ball to do such as respond to music or display specific patterns, but that was the initial intended functionality.

I thought others might be interested in the project, so I am sharing it with you. It would be interesting to see what other functionality somebody might come up with!

Step 1: Cut Out the Shapes Using the Othermill

This is a little more involved due to a limitation in the Othermill software. We have to cut out a series of pentagons and hexagons. The mill is supposed to cut all the way through the circuit board for the main outline of the shape of the pentagon or hexagon itself, but also must cut multiple windows within the main shape in which the LED’s shine through. For some reason, the Othermill software is unable to recognize outlines which are enclosed within another outline, so my work around was that I had to use two separate files to overlay together.

I decided to create the disco ball from the shape of a soccer ball which is technically called a truncated icosahedron. ( This means it takes 20 hexagons and 12 pentagons to create the entire ball. This takes a considerable amount of time to cut this many shapes. It is possible to only cut half the ball since the disco ball is generally mounted near the ceiling and people won’t see the top. This would save about half your materials and hours of cutting time, but if you want to make the full thing, don’t let me stop you! I will note that there is also a considerable amount of soldering involved as well which you would be cutting in half too. You could always plan to make half, see how that goes and make the other half if you're up to it.

Load the two sets of files for one of the shapes into into the Othermill software. I would recommend only loading the set of files from one shape at a time to avoid confusion and potentially incorrect cuts. I have created a registration rectangle cut in the lower left corner of the two files of each set because this is the corner where the software bases the orientation from. If they are lined up there, they should be lined up overall.

The order you choose to make the cuts is very important!

First: Cut the circuits

Second: Cut the interior windows (the multiple small rectangles within the shape itself where the LED's shine through)

Third: Cut the outlines of the shapes

Step 2: Paint the Pieces

After the individual pieces are cut and cleaned, you can then paint the backs.

Make sure that you have removed any remaining dust or debris. Roll out a few strips of painters tape sticky side up so that it is wider than the shape itself, and place the individual cut out pieces, copper side down, to the tape so that the back is facing up.

In a well ventilated area, spray paint the backs of the pieces of cut circuitboard material. I chose flat black for mine because I wanted the focus to be on the LED’s and not the structure itself.

Step 3: Solder

It is time to solder on the LED’s. Cut the individual NeoPixel’s from the strip on the indicated cutting line. Next, place the NeoPixel face down on the circuitboard so that it is facing through the window. Be sure to note the direction of current.

NeoPixels can’t be wired backwards! You must be sure that the little arrow on the front is pointing the correct direction. On these particular strips, there is a small surface mount capacitor next to the LED which should go on the output side or trailing side of the led when you are soldering it in.

If you have it properly oriented, the positive terminal should be towards the center of the shape and the negative terminal around the outside.

I got in the habit of checking the circuit after every individual LED because it saves time in the long run. It's frustrating when you've soldered a whole shape and you realize its not working at the end and you have no idea which LED is the culprit!

Through the process of originally developing this project I have run into a number of unexpected issues. I have updated the design accordingly, but will give you some good tips so you don't have to go through the pain and suffering that I have!

Step 4: Assembly

To attach the individual pieces together, I used hot glue. Don’t rush the assembly. Be very meticulous when attaching the separate pieces together.

Use masking tape on the outside (painted side) to hold three pieces together tightly starting at the bottom panel which is a hexagon. It is very important to note of the orientation of the input and output wires leading from one piece to the next so you can easily connect them in series.

Put a small dab of hot glue on the edges near the corners to temporarily tack the pieces together. Using a small amount will allow the glue to dry faster, and will be easier to undue if you need to readjust.

Once you are happy with the joints between all three pieces, you can add more glue to it. Keep the tape on the outside until the hot glue has cooled. If you are careful, you can get surprisingly clean joints when looking from the outside this way.

Continue adding pieces this way making sure that you put the right piece in the right place. I ordered the pieces starting from the bottom, and building around in a circle, then continuing up.