Bubble Display Overview Video

I spent a lot of time last summer and fall building this 62″ wide bubble display. So much time that I didn’t get a chance to edit together and post an “overview” video showing the whole thing in action. Well, here is that video. If you are looking for more build details just read all my posts tagged with “Bubbledisplay”. If you just want to sit back and watch the whole thing come together via videos, start watching my “BubbleDisplay” channel on YouTube At the beginning.

Finishing the trim pieces

I am finishing up the trim pieces for the bubble display. The last component is the top cover that will hide the top of the acrylic tubes (and hopefully keep bugs out of them!).
3/4 of a 2" pvc tube spray painted silver

I cut the side off of a piece of 2″ PVC pipe and notched the ends to fit over/around the vertical end support and various mounting hardware. Then I used a universal metalic spray paint to give it a metalic look. Unfortunately, they didn’t have “alunimum gray” as a color option in spray paint that works on plastic, so I had to go with “Satin Nickel” which has a subtle bronze/gold tint to it. I’ll try it on the actual bubble display and if it doesn’t match closely enough I can always use it as my plastic bonding base coat and paint over it.

bright alunumum screen covering the end of the tube
I used high temp hot glue to affix bright aluminum screens into the ends of the top piece, which will hopefully minimize the incidents of insects trying to get a drink and falling into the tubes. Admittedly, this may be a bigger problem in my not terribly well sealed garage than the office building where the bubble display will live…but it doesn’t hurt, and it also makes the ends of the cover look more professional.

Text on the Bubble Display

The text of the logo is recognizable even in water. With glycerin I think it will be even nicer looking.

I’m actually cheating by rendering text as a bitmap image and then using software to load the bitmap into the arduino. So really, this is a video that demonstrates my ability to display arbitrary graphics, not actually generate text. (But I do plan on embedding a simple font table in the arduino so that the arduino can just render generic text.)

Bubble Display Frame Trim

Now that I have the electro-mechanical systems working, I am focusing on finishing the trim pieces for the frame that will hide the electronics and top of the tubes.
Plywood panels stained dark mounted on the bubble display base

This mostly consisted of notching a few slots in the pieces of plywood for the aluminum bottom pieces and cables to go through, and a day’s worth of work with a spray gun.
bare plywood laying on a plastic dropcloth with an air compressor and spray gun
stained plywood sitting outside drying

I had initially planned on using bright aluminum window screen mesh in a half tube shape over the top of the upright acrylic tubes, both to keep bugs out, as well as to give a nice visual appearance. But once I tried it out, I didn’t like the appearance, and couldn’t think of a good way to mount the ends of the screen cleanly. I am now considering using the old standby PVC pipe (probably painted some solid color with plastic spray paint). The other option is to buy a large clear acrylic tube (square or round) and use that in the same place. This would allow people to see the tops of the tubes (perhaps too well…it’s too bad McMaster doesn’t sell frosted acrylic tubes…) This is my current prototype:
using a 2" PVC tube (cut lengthwise) as a prototype top cap

Bubble display fiber optic relay

Because the air hose is connected to the center of each square acrylic tube, the 60 LED lights on the bubble display are mounted almost between tubes, very close to the left edge of each tube. This means that a particular LED contributes light to both it’s own tube, and the one to it’s left. On the far right side of the display this makes mounting the first LED easy, as it is well away from the outside aluminum support upright. However, on the far left side of the array, the hole for the LED is right up against the aluminum support upright. The LED’s have a square circuit board below them that makes the entire unit wider than just the LED, and it won’t fit.

bundling together several fiber optic cables using heat shrink tubing
fiber optic relay bridging gap from LED to hole under the last acryllic bubble tube

I knew this would be an issue from the beginning, and had designed my way around it using a bit of fiber optics. Of course, the far left tube is slightly dimmer than the others…but then again, so is the far right tube (which only has one LED).
the last tube is slightly less bright due to the fiber optic relay

60 tubes working!

Yes, I finally have all sixty tubes mounted and working. I still need to swap out two or three of the under-performing motors, and calibrate all motors, and do a lot of cosmetic finishing work (cover pieces for the top and bottom), and some software tweaks….but it’s finished enough to actually work!

22 of 60 tubes running – First scaling up problem rears it’s ugly head.

Here is a video of 22 tubes running with water:

Now for the bad news….22 tubes actually measure 22 1/8″ wide. (apparently each tube is actually 0.00568 inches larger than 1″) This means my entire display would be 3/8″ too narrow, which just won’t work with the tolerances I have designed into my tube holder. That is why I only have 22 tubes in this video….the 23rd tube was just far enough off to not fit into it’s proper hole.

I fixed it by cutting the tube holder into 3 pieces and mounting them with a 1/4″ gaps between them.

A gap cut into a board

I also had to space the end pieces of aluminum farther out, which meant I had to drill 4 new holes to mount the side brackets to the bottom board 1/2″ farther apart. Luckily the T-Sloted aluminum mounting system allowed me to easily move my L-Brackets up slightly to hit the new holes.
mounted to two new holes 1/4" farther out

Unfortunately, I mounted the Shift MOSFET circuit boards on TOP of the screw heads holding the tube support board, so I had to take them all off to re-position the tube support board. Annoying, but not the end of the world.
circuit boards hanging off after I removed them to unscrew the board

So, after a bit of additional work, I now have all 60 tubes working.

Electro-Mechanical systems complete


All sixty RGB LED’s and air pumps working under computational control. Next up, physical assembly.

Bubble Display update: 24 motors connected


Here is a video of the bubble display base with 24 (of 60 total) motors connected running a test pattern. Next up….lots more soldering. I’m very glad I was able to find strings of 20 RGB leds already connected!

First Light!

I have mounted and wired all sixty RGB LED’s under the tube support shelf. These RGB LED’s are in serial strings of 20 each, and I was able to connect them end-to-end, making the wiring much easier than the air pump motors! Each liquid filled tube in the bubble display will sit above one of the LED’s.
60 color controlled LED's mounted under the tube support shelf

Looking down through the holes in the tube support shelf, you can see each tube has a colored LED under it.

These LED’s are individually addressable by the Arduino that controls the entire system. In the video below I have them simply doing a simple color progression for testing.