LED Laminar Fountains

3-D printed laminar flow jet, unlit and lit.

My EDW group has been making great progress on our liquid light display…and it’s a good thing, too, because the display goes on, well, display, two very short days from now.

The overall goal of the project is to create a “liquid light mixer”, with three streams of luminescent water — one red, one green, and one blue — meeting at the center of an enclosure, mixing and creating white light. By allowing the user to vary the intensity of the light in the three streams, we’re hoping to physically demonstrate that it’s possible to create any other color of the rainbow by mixing some amount of red, some green, and some blue.

As of today:

  • the enclosure for the display (a 44-gallon hexagonal aquarium, acquired last week off Craigslist) has been backed with black panels to provide a dark background for the glowing jets of water
  • the cabinet stand for the aquarium has been painted black and fitted with a shelf to keep our power supply off the ground
  • the aquarium has a new black lid with wiring holes
  • the plumbing for the display is ready to go
  • the control box for the display has been laser-cut (and I couldn’t be prouder to say that the group designed the control box pattern entirely on their own, without needing any help from me)
  • the controls themselves are ready to be wired up, modulo some debugging

And, last but most definitely not least, we’ve 3-D printed the first of our new laminar flow nozzles.

Though each nozzle takes about five hours to print, compared to around an hour to make one of the original PVC nozzles, it’s absolutely worth the extra time: the new design takes the original nozzles’ elaborate construction of scrubber sponges, mesh window screen, drinking straws, and PVC test caps, and turns them into a simple three-piece construction that disassembles for cleaning and has a built-in through-hole for an LED. And, of course, it can print on its own, instead of requiring multiple people for assembly.

Rendering of the laminar flow nozzle design, created by Jemuel Stephenson

Rendering by Jemuel Stephenson.

Jem, one of the other mentors, worked his magic and whipped up the original design last Thursday; we did a test print on Friday and discovered that the initial “straw” portion was too finely-detailed for our 3-D printer to handle. So Jem revised the design over the weekend, and our nerve-wracking second print (we didn’t have a whole lot of time to make changes to the design if it didn’t work!) produced this beauty:


In order to test the nozzle as quickly as possible, we filled in the first chamber with hand-cut circles of scrubber sponge instead of taking the time to print the sponge layer the design calls for…but even with that change, it worked like a dream. (Take a look at the first picture, and just how well the light shows up in the stream of water.)

We’re in the process of printing the three final nozzles using black ABS so that they blend into the display better. Once they’re done printing, it’ll be go time to anchor the nozzles, wire up the controls, add the finishing touches to the enclosure — and then, finally, to show off one July’s worth of engineering. I can’t wait.


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