Intro: Rainbow Shadow Museum Display
My school is located on the site of a museum, the Western Science Center. WSC has bones from ice age creatures (mammoths, mastodons, sloths, etc.) that were dug up when creating the Diamond Valley Reservoir. The school adopted a "Museum Discovery Learning" model of project-based, technology-infused, collaborative education. This year they decided to take it a step further and we are going to create our own hands-on museum similar to Exploratorium or Ruben H. Fleet. I am in our Engineering Club and we will do the research and development of the displays and then our MakerSpace class (I'm in that too) will make museum quality versions of the exhibits.
We decided that our first theme will be "Light, Color, and Waves" so I was excited when Make Magazine posted directions for making a color-mixing shadow box museum display. Our Engineering Club decided to build one. The author was Nicole Catrett (http://www.nicolecatrett.com/#/eastward/).
Step 1: Color Shadow Box Museum Display
What follows will not be instructions for how to build the display because Make Magazine did a pretty good job with that, but it will be about what we learned from the not-so-complete instructions, some modifications that we made, and the adjustments that need to be made at the end to get the best display possible.
Here are the build instructions: https://makezine.com/projects/rainbow-color-lightbox
Step 2: Construction Part 1
There are really two parts to the build, the box and the electronics.
The box is a typical 4-sided box. The dimensions are unimportant. We made ours a 24" square because the sheets of acrylic come in 24" lengths. You could just screw the acrylic to the top. Our MakerSpace put grooves in the wood to slide the acrylic into.
Then, you make the mylar tubes. We got a large roll of mylar and cut rectangles out of it. Then, we wrapped the rectangles around different sized cylinders and taped them. We made several different sizes to improve the visual appeal including some really small ones to fill in gaps.
Step 3: Construction Part 2
There are 4 parts to the electronics, power supply, LED driver, RGB LED, and heat sink/fan.
We used a variable voltage universal adapter. We cut off two of the connectors. One went to the LED driver and the other to the fan. This works great because the brighter the LED gets, the faster the fan spins. It is really old and I cannot find anything similar on Amazon, but you could easily solder wires to split something like this: https://amzn.to/2LfZAkZ
We realized that the LED driver can go up to 34 volts and we are only pushing it to 12, so we are going to try a higher voltage source to see if the LEDs get brighter without getting significantly hotter. We will use this: https://amzn.to/2xF27n6
The LED and LED driver are described in the Make Magazine instructions and are pretty straightforward. The instructions show you to drill a piece of metal to use as a heat sink but this LED gets very, very hot even at 12 volts, so we decided to use active cooling. We took the heat sink and fan off of an old video card, but a CPU heat sink and fan would work too. Make sure that there is thermal paste between them and solder all of the wires tightly and seal with shrink tubing or electrical tape. With this setup, the LEDs don't get hot at all even after running for an hour or more.
Step 4: Adjustments
There are several factors to consider when setting up your rainbow shadow box. The instructions are not incredibly clear where the diffusion filter goes, whether there is one or two, and whether it goes on the top side or bottom side. So, we experimented with all of these.
With the diffusion filter only on the bottom, we get vivid colors but they can only be seen from directly above.
Each of the photos has been labeled with the setup that generated the image. Click on the image and hover over the square to read the description.
There is really a trade-off between the sharpness of the shape, the vividness of the colors, and the size of the shadows. You can decide which you like the best, there is no correct answer.
Step 5: Videos
Here are some videos of the different effects.
This video shows the intense colors that can only be seen from directly above when the diffusion filter is on the bottom.
Step 6: Video 2
This video is the Rainbow Shadow Box with two diffusers and the LED far away (approximately 30 inches) and the starfish near the box (approximately 6 inches)
Step 7: Video 3
This is the box with two diffusers and the light close to the box (approximately 12 inches)
Step 8: Video 4
These videos show what it looks like when there is a diffuser on top, but none on the bottom. It makes cool patterns that move when you pass objects through.
Step 9: Video 5
This video shows the diffuser on top and none on the bottom while moving the light source.
Step 10: Conclusion
Although this Instructable does not prescribe perfect settings, it aims to demonstrate what each setting does so that you can choose. If you like the psychadelic swirling feature of a single diffuser, feel free. If you like vibrant colors, then move the light closer. If you like more faded colors that take up more area of the box, then move the light farther.
I hope this helped. Please leave pictures in the comments area if you make one of your own.