A contribution designed, created and written by Davis Hart
(with some editing and comments added by The Fiber Optic Store.com)
The Goal: To design and build a 2×4 foot, self-contained star field to be suspended from the drywall ceiling of a bedroom. The light source will be located on the star field panel itself, so as to minimize run lengths of the fibers. This particular project was probably more difficult than it needed to be, as I decided to closely mimic the night sky with varied star sizes (fiber diameters), real constellations, and a custom light source.
The light source was comprised of three high intensity LEDs, with individual brightness controls. CLICK HERE to go to the illuminator that Davis built.
I would highly suggest reading the Fiber Optic Store’s section on: How to create an indoor Star Ceiling as they cover some important information that I will assume you know already if you are going to undertake a project like this.
NOTE: Most Photos are Thumbnails. Click on the image to view a larger version.
The Star Field
Foam: I was unable to locate a black piece of foam, therefore I used a white piece of 2’x4′ soft foam which I purchased from the local fabric store. This piece was in the “half off” bin, so it was not the cleanest. However since it was going to be painted I was not concerned. The important thing was that it was flat.
Painting: Using flat black, good quality spray paint, I painted one corner of the foam for testing. Using a large sewing needle, I threaded a few fibers that I got in a sample pack through the foam. Because the needle bends the fiber 180 degrees, the end must be clipped off to keep the fiber straight. However, I found that, if carefully aligned (perpendicular to the foam), 0.75mm and up diameter fiber can actually be pushed through by hand, saving a little fiber.
SPECIAL WARNING: If you cannot find black foam, and need to spray paint white foam, be sure to use a gas mask. It took 2 cans of paint to cover one large side of the foam: the other side remains white. If your paint looks uneven on the foam (mine sure did), don’t worry: you can’t see the problem spots once the foam is mounted on the board. (Unless a liberal amount of front lighting is applied to the board.)
Gator board: The foam will be glued, black side down, to a piece of Gator Board, which is normally used to mount large pictures on, as it is very dense and durable. The one downside is that because it is dense, one cannot sew through it. I got a 2’x4′ piece at the local professional photo finishing store for $20.00.
Star layout: I’ve decided to first layout my stars on the Gator Board, and drill the holes, before gluing the foam to it. I first laid out a grid of eight squares, each one square foot, to ease the process of counting stars.
Fiber Optic Store Comment: Davis wanted his star panel to closely mimic the evening sky. He used three different diameter fibers. .25mm, .50mm & .75mm. He also designed a spreadsheet to help him estimate and keep track of his fiber.
Constellations: Another feature I’ve added to this display is seven real constellations. In order for these constellations to appear correctly on the front of the display, I laid all of the stars out on the front of the Gator Board, that is the side that faces the audience. Later, I will have to transcribe these marks to the back, since I’ll glue the foam to the front, covering the existing marks.
Marking stars: I added stars to my board using a silver pen, and intermittently entered the stars into the spreadsheet to get an idea of how many stars I have left. I stopped marking when I had about thirty feet of the 0.25 and 0.5mm fiber left over: I don’t want an overly busy sky, and I don’t want to drill more holes than I have fiber for.
Drilling: I found that for my needles, I needed to use a 3/32″ bit for the 0.25 and 0.5mm fibers, and a 9/64″ bit for the 0.75mm fiber. To make things easier, I drilled all of the holes with the 9/64″ bit. Using the silver pen (a white pencil would work well, too), I remarked the holes as I drilled them, to protect against later confusion.
Transcribe marks: Once Drilled, I transcribed the marks on the front to the back side (since I marked the constellations as one should see them, we will have to glue that side to the foam, so that it points towards the audience, and therefore need to mark the holes on the backside). At this point, I had a 2’x4′ piece of foam, painted on all edges, and on one face, a 2’x4′ piece of Gator Board, holes drilled, with diameter marks on both sides.
Gluing: To glue the two pieces of this project together, I chose to use silicone rubber. I don’t know how well other types of glue would work, but if you are going to use something else, try it on a test piece first! I laid the board out on the table, making sure the side facing the audience was up, and proceeded to squeeze a large, flat bead of silicone on the board, making sure to avoid the holes. After applying a fair amount of silicone (see picture), I put another piece of gator board on top of it, and then added weights to compress the foam into the glue. You could use something else on top of the foam, just make sure its flat and covers the surface of the foam. Don’t be surprised when the glue has dried (overnight), that some of it has squeezed out around the edges: you can simply cut it away from the project with a scissors.
Light location: I planned to build this display with three light sources. I have marked my light source on the middle of one of the long sides of the board (I used this location in my measurements earlier). Because I haven’t built the illuminator yet, I made three marks: one on the center line, and one on either side of it, one inch away. These three marks represent my LEDs. Also, since I don’t know the details of my illuminator, I don’t know which star runs where. Therefore, I will run each fiber to the furthest LED, thus guaranteeing adequate lengths.
Sewing: For more information on sewing the fibers, check out The Fiber Optic Store’s web page When I sewed my fibers I didn’t pull the fibers through as far as they did (to conserve cable because I’m very money conscious) – in fact, I pulled mine through about 1 inch past the 90 degree bend in the fiber formed by the needle. Getting the larger fibers through the foam requires a bit of force, so I recommend once the tip of the needle pokes through the paint on the foam, place your index and middle fingers on either side of the needle to minimize the chances of the needle pulling or tearing the foam off of its glue.
Cutting and filling: Once the fiber is through the foam, I simply cut it to reach the furthest LED with about an inch of fiber extra. Since I planned for 6 inches of extra fiber per run, I’ll still end up with more left over. I worked one square foot at a time. After sewing the whole square foot, I came back with the silicone rubber and a toothpick, filling the holes with silicone rubber to hold the fiber in. I only used enough to attach the fiber to the board. Check out the picture to see a finished square foot – the fibers taped together form one of the constellations.
Clipping: I let the glue dry overnight, and then in the morning, cut the bend in the fiber off of the front side of the board, thus leaving a field of fibers sticking straight out of the foam, the desired setup for the star field.
(some) Organization: As I finished the sections of my board, I tried to control the mass amounts of fiber by taping them to the board in bundles, though chaos still prevailed by the end. I’ll state now, organization is the one word this project lacks from time to time. See the picture to get an idea of the disorganization. If you cut your fibers longer, then you won’t have problems gathering them at one spot (particularly the light source) – the tuft of fibers standing straight up is a perfect example of the limitations of short fibers. When you’re ready to attach them to the light, you can simply cut the whole bundle, and save yourself a lot of time and hair pulling.
Illuminating: The hardest part was gathering the fibers for the illuminator. Since I decided to skimp on fiber wherever possible, I ended up having a few fibers which were very hard the get to the light source. Also, since I had decided to use three lights, I had fibers crossing from one side of the board, across two bundles, to the furthest LED.
I bundled all of the constellations (luckily I had been bundling the individual constellations all along, so gathering those was not too hard) at the middle LED. To hold them temporarily, I wrapped tape around the bundle. Next, I simply grabbed at the rest of the fibers, and divided them into two bundles, taping them in the same fashion. Once I had all three bundles, I carefully fanned out the fibers and found those that were pulling out of the tape, and pulled them towards the end of the bundle, so as to make the end as even as possible, and to know how far back to cut the fibers. Because the fibers are pretty slippery among their own kind, once I had a bundle taped together, I shot a bead of silicone rubber into the back of the bundle, where all of the fibers run into the tape, and let it dry overnight, leaving me with a secure bundle in the morning. You can see my illuminator in construction here, also.
Fiber Optic Store Comment: We applaud Davis for his creative initiative in building a custom illuminator for his star panel! We’d like to point out that we also offer an ULTRA BRIGHT LED illuminator that would work perfectly for this type of project. It is powered by a 9 volt battery and could be easily built into the panel. CLICK HERE to go to our 1000M illuminator page.
To secure the bundles to the illuminator, I ran a thin piece of wire through the breadboard (the board the illuminator is build on), and tied it around the bundle. Overall, the last part of this project is a bit hack, though the hacks work great. In this picture you can see the purple spacer wire and how the board is screwed to the project. Click for more detailed information on the illuminator.
Masking: In order to hide the mess of fibers on the back of the board, I had to attach masking around the edge of the board. I used gator board, cut 4″ high, wrapped around the board to accomplish this goal. In the picture, you can see not only how I glued the masking to the project (with silicone rubber), but also the method by which I have hung the board. I simply cut a piece of aluminum angle into 4 pieces, each about 4″ long. I sanded one side to glue to the board, while I drilled hole in the other to attach chains.
Here is the finished project. You can see the chains that I used to hang the board from the ceiling. The break in the masking resulted from a shortage which I didn’t want to resolve by purchasing a whole new sheet.
- Constellations might not be a good idea – I lost a few stars by the end of the project probably because they slipped back into the bundle while the silicone was still wet. Therefore, most of the constellations are missing a star or two.
- ORGANIZATION. I would say the best way I could improve the project would be to cut the fibers longer when I was threading them so as to avoid the few short ones that hindered some of the bundling later on. Though, having the light source so close to the stars will still complicate the project.
- Fewer LEDs would simplify the bundle area (you can see the mess of fibers going into the illuminator in some of the pictures).
- You might think, like I did, that you need 25 stars per square foot. Your wrong. I turned my board on, with a total of 175 stars in 8 square feet and I almost fell over. I would say that the upper limit should be 16 stars/sq. foot.
Thank you Davis for an outstanding contribution to our site!
Do you have a fiber optic project or model that you built? Would you like to show it off and share it with the world? If so, let us know! You could earn some free fiber optic filament! Click here for details