Introduction: Pink Floyd Light Dispersing Poster
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This was meant as a birthday present for my girlfriend who's an avid Pink Floyd fan, but it got pushed a few months and turned into a Christmas gift! The original plan for this project was to have a small poster to hang up with a light source and a prism to disperse it into the spectrum. Eventually I had the idea to add the fiber optic lighting, and once the thought was there, there was no getting rid of it. The dispersion of light from the source into the spectrum, lighting up the “Pink Floyd” fiber optics, and the star fiber optics can all be controlled independently, with various modes for the star fiber optics. I won't go over all the R&D (or trial and error if you prefer) I went through to get it to work, otherwise I'll never get through this Instructible, so I'll just focus on what worked and got the project to its functioning state.
It's hard to estimate the cost of the whole project because I worked on it over the course of 8 months or so on and off and between other projects. I was also able to get some of the parts (mainly the optics) from work, but if I were to hazard a guess I would say overall it cost ~$100-$150. The measurements I provide will also be more of a guideline than an exact measurement for replication as your optics may be different causing different light paths.
The project consists of several parts, many of which were done concurrently, but I will do my best to section them out. To do so I'll break the instructable into the main sections of the project. Starting with the parts.... Parts Electronics strong light source or strong flashlight( I used three 300 lumen surface mount LEDs - make sure to check the data sheet to see if they have a spectrum that stretches from violet to red if possible) I won’t go into too much detail into making your circuit since it is a simple in the sense that it only needs to be able to turn a light on and off. some switches to turn the lights on and off wire some resistors (depends on your supply and LEDs) Power source (I bought a variable one from 3.3-12V so I could adjust to my circuit) 2 small PC fans to cool circuit (I had to dissipate a lot of power, your circuit may not need to) 4 fiber optic bundle desk ornaments
- 3” Glass Prism (I got mine from eBay, you can get a different size if you like)
- small mirror
- several convex lenses / magnifying glasses (you should only need one, but different lenses will bend light differently so you should try a few to see what works best if possible)
- wood for frame will change depending on the size of your photo / frame (I used two 1”x2”x4’ for the frame and one ¼”x4”x2’ for the light enclosure)
- foam core board the size of your frame
- aluminum angle bracket to act as….well a frame for the frame (see image) to help hide the foam
- printed poster as backdrop
- some screws
- glue (I used weldbond)
- wood stain
- lacquer (I used spray lacquer) wax (optional)
Step 1: Light Source
At first I tried using a regular LED flashlight and had some good results. So I decided to go big and make my own circuit using five 300 lumen surface mount LEDs. Now for those who are unfamiliar with the lumen scale for brightness, a typical high powered flashlight is usually 100-300 lumens, so this had a cumulative 1500 lumens! This was also done preemptively to get the brightest, cheapest source (within reason), which I could later tone down if needed. Once the project was all done I did just that, since two of the LEDs were basically cut out after the first beam splitter. The circuit board was nothing fancy, just LEDs with their corresponding resistors, a fuse, and some terminals to connect the switches.
Due to the power supply I found I had to drop 3V at 700mA per LED, so it’s safe to say that there was a decent amount of power to dissipate (3V * 0.7A = 2.1W). I added some large 5W resistors, a heatsink onto the circuit board, and for good measure used a pair of fans I had laying around to circulate some air over the board.
Step 2: Light Path
Now that I had my crazy light source I had to figure out the light path for the dispersion so I would know how big of a photo / frame to make. Since I didn't know the refractive index of the prism I bought (and couldn't be bothered to figure it out), I had to see how the light would bend so I could get the most of the spectrum on the print as I could. The last thing you would want is to have the majority of the spectrum splitting out of your frame. There also had to be some container to block the waste light from bleeding out and diminishing the effect of the spectrum, in addition to housing the optics.
After fumbling with various combinations of light sources, magnifying glasses, projector lenses, mirrors, beamsplitters, and collimators, one combination finally worked. The best setup that worked for me was a box with a beam splitter in front of the light source, a mirror angled at 45 degrees to bend the light (to keep the light box against the side of the frame instead of sticking straight out), a second beam splitter, and finally a convex lens to refocus the light. This allowed for a beam of white light to be visible before the prism. The red arrows in the sketch are meant to give a rough idea of the light path and how it gets focussed.
Now you don't have to follow this example necessarily (and probably won't be able to as different light sources and lenses will have different optical properties). If you want to get your own light path I recommend going into a dark room (the less light the better) and playing around with the distances between the lenses and beamsplitters. Once you have your desired optical path laid out, get a rough measurement of the size of poster you'll need to encompass the section of light you want.
Step 3: Background
With your measurements laid out, get a photo for your backdrop or use a solid colour if you prefer. I chose a space photo for which I take no credit.
(http://www.wallpaperup.com/85079/cherry_blossoms_iy_tujiki_original_space_stars.html) I photoshopped it a bit to get it to the resolution and aspect ratio I wanted (and to get rid of the flowers in the corner), and got it printed at Walmart. Make sure that the photo you use is a high enough resolution to print clearly at the size you want.
Step 4: Frame
Knowing the size of the picture, now we can make a nice wooden frame that will hide all the fiber optic cables. This can be made any way you like. I chose the to make the frame this way because of the way I had my fiber optic bundles laid out. It allowed me to anchor them to the frame.
Simply cut your 4 pieces to size and join them how you please (miter, butt, dovetail etc.).
Next you'll want to cut your foam core board to the size of your frame and glue it on. In retrospect I would have used a thinner foam core because it would have made stringing the fiber optics through easier. Once your foam core is glued on you can go ahead and glue your printed photo onto the foam core. I used a spray adhesive, just make sure to use it outside as this stuff gets everywhere.
Step 5: Staining and Sealing
Now that the wood work is complete you can go ahead and stain / paint the wood however you like. I chose an ebony stain to keep the frame dark and gave it a couple coats of lacquer followed by wax. I won’t go into too much detail for this step as there are several excellent instructables and youtube videos on the topic. The key point to remember is to use short bursts of spray lacquer (spray is my preference) and add several thin coats.
Step 6: Improve Spectrum Visibility
Now that you have the frame built you can attach the light box with some brackets. The next step is to test out your light path and make any minor adjustments you might need. Once you have it pinpointed you want to use some masking tape to outline the spectrum on your print. Next you can brush a thin layer of the Weldbond onto the area of the image that the spectrum takes up and sprinkle some white sand onto it. This will help make the spectrum more visible as it almost disappears on a black background.
Step 7: Fiber Optics
Now the best for last..err I mean worst. This section is the most time consuming and if you decide to skip over it you won't hurt my feelings. Threading the fibers through will take a while, but the effect at the end is well worth the hours spent on Netflix stringing thin fiber optic cables. This is where a thinner foam core board will save you time, because a thicker board will make it more likely for the fiber to get stuck in the board, which will lead to minutes of expletives before finally stringing the fiber through.
For simplicity I bought some of those desk ornament fiber optic bundles from China through ebay because they were the cheapest option. They also had their own internal circuitry to make them glow / flicker / change colour which saved me an arduino.
The method that worked best for me was to use a pin just bigger than the fibers, poke some holes through (from the picture side) and proceed to string the fibers through as far as possible. Remember since the bundles are connected that you need to plan where the bundle will sit to be able to reach where you need it to. I ended up using 3 bundles and still had fibers to spare.
Once you get a good chunk of fibers connected you can go ahead and glue them down. I used some weldbond in a syringe to apply to the fibers to glue them down to the foam core. Careful with crazy glue as it may trickle down the hole into the front of the poster. Once the glue dries you can go ahead and trim the fibers flush against the photo.
Step 8: All Done!
At this point I just added some black aluminum corner brackets to frame the poster. Now just lay back, play your favourite Pink Floyd tune and enjoy the light show!
p.s. I apologize for the portrait video, it was the best way to capture the entire frame. The video does not do the spectrum justice as the camera cannot capture it quite right.
Also, if you enjoyed this Instructable please vote for me in the make it glow contest https://www.instructables.com/contest/makeitglow2015/
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