Repurposed CD Rack Light Sculpture

One night, I found myself mindlessly scrolling through Facebook Marketplace not particularly needing / looking for any one thing (as one often does as a passtime). That was until one piece of "scrap metal" caught my eye - this cool looking CD rack that was looking for a new home for the low price of next to nothing!

Did I need it?

- No, not really.

Did I even have CDs to store on it?

- Hardly.

Did I know I would even have a proper spot for it?

- Maybe.

I was sold - my mind was already running wild with what I would do with it. I sent a message to the seller and picked it up the same evening. The fun part of getting to turn ideation into reality then began.

It quickly became clear to me that the item's original design intent to hold CDs was beginning to dwindle (if picking up the rack with an inch of dust from the seller was any indication). It's understandable - CD collections might be on their way out (I surely didn't have any CDs that I would be storing on there), but that didn't stop me from thinking of ways to repurpose this item and making it more relevant to me in a modernized way.

In being a hobbyist Stage Lighting Designer (and really missing it due to the pandemic), I knew I wanted to pay homage to that and give my home a little extra flair with this soon-to-be lively decor piece. My plan was to turn this once-viable CD storage rack into a more personable light sculpture that would fit right in to my music-themed office (while reminding me of the fun that is being able to light a live show). 🎸 🤘

To achieve the goal, the plan is to use some addressable LED strips to line the inner "neck" of the Guitar Rack and add some diffusion paper to the inner-front to hide the diodes and more evenly spread the light. My intent is that doing this will make it stand out to create some really cool lighting effects!

• Guitar Shaped CD Rack (a quick google or ebay search might turn up some results, but the same project can be applied to any other CD rack / other object that you think could use some cool illumination)
• WS2812B Led Strips (About 2.5 meters total are needed for the project, so I opted to order the common package size of 5 meters, which leaves some extra for future projects!)
• ESP8266 Microcontroller to drive your LEDs (connection & programming guide below)
• A 1000uF Capacitor and a ~470Ω Resistor for the LED Strips (optional - see below)
• 5v Power Supply (with proper amperage to cover your LEDs - more details on that later)
• Other misc electronic prototyping items like a breadboard, jumper cables etc
• Your light diffusing material of choice (see below for some options)
• Crafting materials like tape, spray adhesive, cardboard / foam-core

Note: Some of these Items I already had on hand from previous projects, so your final cost of the project may vary. Most of the components should still total sub $100 (excluding the CD rack / whatever you are lighting up!).

For this project, I opted to use WLED; a well-maintained, feature-rich project for easy LED strip control over your local network! I chose to use WLED over custom code mostly due to the vast library of effects already baked into the project and the ease of usability when getting started.

• Following the WLED Quick Start Guide, I started by visiting the releases section and downloading the basic "WLED_0.11.1_ESP8266.bin" binary, since we're using the ESP8266 (version 0.11.1 is the latest at this time of writing).
• Next, I connected the ESP8266 to my computer via USB, downloaded the ESP Home Flasher to my computer (following Method 2 in the guide), then used it to flash the downloaded binary onto the device.
• Once flashed, I connected to the WLED interface via the access point the device creates for initial setup. I specified my network credentials in the WIFI setup and set the "mDNS address" to "wled-guitar", and after a restart, VIOLA! ... The device was on my home network and accessible at http://wled-guitar.local !

This process was fairly straightforward and only took about 20 minutes. If you run into any trouble, check out WLED's FAQ - there's likely some good info in there to help you get up and running.

Now that WLED is flashed onto the ESP8266, we can now begin to follow the wiring diagram to get our LEDs hooked up.

With the end goal of the project in mind, the next step is to begin assembling our lighting circuit that we will use to prototype and will eventually be affixed to the inner part of the Guitar Rack.

Continuing to follow the WLED Quick Start Guide, I began hooking up my controller to the power & LED strips based on the wiring diagram provided there, but with the few tweaks of adding my 1000uF capacitor and 470Ω resistor. I'm not going to dive deep into that here since the WLED guide has most of what is needed. You can also reference my final wiring diagram which I have attached.

Since I was still needing to play with different diffusion options at this point, I opted to start my project by laying out two rows of the the WS2812B LED Strip on a piece of scrap Foam Core (and lightly affixing them with electrical tape).

This approach has a few advantages:

• You can very easily prototype and make tweaks a lot easier on a desktop circuit, especially since the LED strip placement is likely going to change considering our unknown variable of diffusion (more in the next step)
• It's nice to see your LED strips working & in action when it's easier to get to, rather than having to completely undo your project to see what wiring mistakes you might have made!

💡 Some Beginner's Tips to Hooking up LEDs:

• Addressable LED Strips like the WS2812Bs have a "direction" in which the data flows. When connecting your cables (if not already connected), it's especially important to pay attention to this, as hooking things up backwards will result in your LEDs not illuminating when you instruct them to turn on. Power however, can be connected anywhere along the line.
• Using a Resistor of 300 - 500Ω (I used a 470Ω one) between the ESP8266 digital output pin and the data input pin on the LED Strip is highly recommended, as this will reduce the noise on the line and can even help prevent damage to the first LED. Resistors don't have a "direction", so you don't have to worry about putting them on backwards. It is best to keep this resistor closer to the end of the LED Strip, though (for prototyping, I left this on the breadboard, but will eventually solder it closer to the LED strip).
• To provide a more regulated current to the LED strip, it's also recommended to place a 1000uF Capacitor that is rated about 6v or higher between your project and the power supply. Capacitors do have a "direction" that's worth noting in this context (denoted by the [-] stripe on the side); make sure your capacitor is connected the correct way, with the stripe on the negative (-) line of your circuit.

I learned about the the Resistor and Capacitor tips through a prior project - this guide has a really good explanation if you are interested in reading further.

Once your LED strips are connected in a fashion similar to the wiring diagram, it's almost time to pop back into the WLED interface and turn them on! (It's also a really great idea to double and triple check your wiring at this point + before attaching power)!

Back in the first step, I set my mDNS value to http://wled-guitar.local which will very much come in handy as a shortcut at this stage! Plug in your newly formed circuit, and under the assumption that nothing sparks or explodes, pop into the WLED Settings > LED Preferences page where the LED Strips can be configured:

1. I temporarily set my number of LEDs to 65 (the # LEDs on my foam board) and saved the settings. This value will need to be updated later when we mount the final number of LEDs to the CD rack.
2. Note the "Color Order" setting - If you turn on your LED strips and the colors do not respond as expected, you may have to play with this setting depending on the type of LEDs you purchased. WLED's default order of "GRB" worked with the LED strips I had, so I did not have to change this setting.
3. Moving out of settings, Select the Colors Screen, pick a Color and hit Power! Your LED strips should be shining bright! 😎
4. Pay special attention that the Primary Red, Blue and Green colors display correctly when selected, as well as that intermediate colors display as expected (otherwise you may have to tweak the Color Order setting).

At this point, feel free to play around with the Colors, Palettes and Effects within WLED to get familiar with the software. You may want to also check out the companion WLED App that can be downloaded for both iOS and Android which makes mobile control of the LED strips on your home network a lot easier!

Note: Skip down below if you know what diffusion material you want to use ... this section only highlights the trial and error I did with finding the right material for this project.

One day I came across this opague-white "drawer liner" at a local dollar store that I thought would be perfect for diffusing the LEDs in this project!

I planned to do a diffusion test with some easily attainable household items, so I setup my test with the following:

1. Baking Paper
2. This Drawer Liner
3. Plain old Printer Paper

Test A:

As you can see in the attachments, I cut each sample into a smaller swatch that I could use to compare with. I started by hovering each swatch about 2 - 3 inches over the LED strips to see what kind of diffusion effect each sample outputted.

At this stage, my thoughts were as follows:

1. The baking paper seemed to have the most uniform spread when it came to colour

2. The drawer liner seemed okay, although there were visible LED hotspots that were emphasized by the "peaks and valleys" of the material

3. The printer paper also seemed okay, but only on the areas immediately over the LED Strips - there was a noticeable "dead spot" right in the middle, and the deep blue color only shined through in lower-light situations.

At this point, the Baking paper seemed to have the slight edge over the others.

Test B:

I then took the individual swatches and taped them to the inner side of the guitar neck, while holding the LED strips (mounted on the Foam Core) flush with the rack to simulate more of what the final product will look like.

At this stage, I concluded:

1. The baking paper seemed to still hold up the best - it had the least amount of variation in terms of dead spots / most even light spread. ✅
2. My initial assumption that the drawer liner would be the winner was immediately refuted as the LED strips were almost completely noticeable at that particular throw distance. ❌
3. The printer paper still held up pretty well, and in this case ended up being the runner up simply due to the fact that it appeared it would not show through as well in daylight. 🥈

Winner: Baking Paper!

With the winning diffusion material selected, it's now time to start preparing all the materials and tools needed for final assembly.

Prep the Guitar Rack

1. I rolled out a large sheet of baking paper roughly the height of the Guitar Rack, then cut it down to the total size of the Guitar's "Inner Neck" (the width ended up being about 7 inches).
2. Using some binder clips, I temporally affixed the paper to the rack and started folding the sides of the paper onto itself to crease it / form it to the final shape (I partially disassembled the rack to make it easier to handle)
3. I took the entire piece outside and sprayed the inside of it with Spray Adhesive and immediately pressed the baking paper to it. For longevity, I added some electrical tape on the sides to keep the paper affixed to the frame (and to hopefully to stop it from ever peeling away).

The Final result is a free-standing, diffused guitar rack that's ready to shine!

Prep the LED Mount / Backing Material

In Step 2, I affixed the LED strips to some scrap Foam Core for prototyping. In the next step, we'll be permanently mounting them to the back of the rack, so we need to cut a new piece of foam core to do this.

1. Starting with a pristine piece of foam core, I measured and cut two pieces to the size of the rack width (5.25")
2. The entire height of the Rack was 63", so the second piece needed to be cut to size once more.
3. I joined the two pieces of foam core with hot glue, then doubled-down with some black electrical tape to follow

The Final result is a single piece of foam core that we can affix our LED strips to!

Mounting the LEDs

1. I pulled the LED strips off of my "prototype board" and cut two strips that spanned the length of the height of the cut foam core piece. This ended up being the equivalent length of 65 LEDs per strip (this will come in handy in a bit).
2. When playing with diffusion + the LED strips mounted on the prototype board, I arbitrarily spaced them out about 2 inches apart. Although the baking paper was the winner of my test and the light spread was almost indistinguishable, I opted to move the light strips a bit closer together to hopefully make that even better. I drew two guide lines on the foam core, about 1.25" apart to help with strip alignment.
3. I peeled off the adhesive backing on my LEDs and permanently mounted them to the board using my drawn lines as a guide for spacing (and paying special attention to the LED strip "direction" I mentioned earlier).
4. I connected on a set of jumper cables between the two LED strips at the top, and reconnected the circuit to test. Once I confirmed everything worked as it did before, I popped back into the WLED settings screen to set the # of LEDs to 130 (same process as what we did in Step #3).

A Note about Power Requirements:

After setting the final LED count to 130 in WLED, you'll notice that the software gives you a guideline on what type of power supply you need. In my case, it's recommended to have a 8 Amp power supply to drive the 130 LEDs at full brightness for optimal results. However, for most effects, 2.5 Amps seems to be adequate (I lucked out since the power supply I had kicking around was rated for 3.5 Amps). The number of LEDs you choose to use in your project will determine what power supply you will need to purchase 🔌

Assembling the Guitar

1. Luckily the Guitar had three screw holes on each side of the rack, so I used those to fasten the foam core to the back of the "neck" with some spare screws I had laying around (although taping along the sides would probably have also worked just as well).
2. With the foam backing now affixed to the rack, I draped the power cables out the bottom back of the unit and placed the ESP8266 / related circuitry on the pedestal that you can't see!

Now all that's left to do is to turn on the strips via WLED & choose a cool effect to take in the awesome eye candy that this thing puts out 😎

I'm very pleased with the outcome of this CD-Rack turned Light Sculpture project and the fact that it's in the shape of a guitar is even cooler (and fits right into my music-themed office)!

My Favourite Highlights:

• WLED has a basic Amazon echo integration, so simple home automation features like scheduling the lights to turn on and off can be easily added
• WLED also has support for DMX / E1.31, so I could in theory hook this up to a lighting console and use this on stage! (Not that I would, but the Lighting Designer in me is Nerding out!! 🤓)

What's Next / Future Improvements:

• I plan to 3D print an enclosure for the ESP8266 so that it can sit neatly at the bottom of the stand and have slightly better cable management.
• I'm thinking of using the Segments feature of WLED in a bit more depth in the future. My Idea here is to add LEDs to each of the exposed circles on the top of the guitar (diffused with bottle caps) to add some more flair!
• It would be cool to route the power cable through something that appears as if there was a patch cord plugged directly into the guitar sculpture. This might be as simple as wrapping the power cable with a "braided sleeve" and mounting it so that it appears "plugged in".
• I may one day play with the Sound-Reactive fork of WLED so that my lights can dance to music!

If there are any questions about my project and process, I'll do my best to answer ✌️
If this has given you any fun ideas for a project of your own, I'd love to hear about it!