Introduction: Concrete Fiber Optic LED Bar

About: I teach at a super awesome public school in Chicago. I teach physics and coach robotics. My kiddos (students) are the greatest kiddos to ever exist!

Hello! This is my first instructable so please be kind and forgiving. When I did this build 5 years ago I did not think I would ever write up a "how to" so I did not take enough pictures and I am missing some important steps in the design/build process.


Quickcrete 80lb bag

Quikrete 10 oz. Liquid Cement Color - Charcoal

Fiber optic star ceiling kit (or just a lot of fiber optic cable)

Thin rebar mesh

4'x8' - 1" pink Styrofoam insulation sheet

4'x8' - 3/4" Melamine Panel

2"x4" lumber

Silicon caulk

WS2812B Individual Addressable RGB LED Strip

Arduino or similar micro controller

Assorted tools - table saw or circular saw, drill, large tub for mixing concrete, screws and stuff.

Step 1: Design and Calculate Dimensions

I decided to go with 2" thick top that is 72"x18". This means I would use just about 1.5 cubic feet of cement.

There are a few ways to do a concrete counter-top but for this one I chose to make a mold so that the top of the counter is facing down in the mold. This part is necessary to get the fiber optic cables through the concrete. I cut the pink foam insulation to exactly 72"x18". For the bottom of the mold i cut the Melamine to 73.5"x19.5" to allow for 0.75" sides of the mold. I cut long strips of melamine at about 5" thick to account for the 1" of foam and 2" of concrete. That left about 2" of wall so that stuff didnt slop out while pouring/working with the concrete.

Step 2: Insert the Fiber Optic Cables

This part took FOR.EVER!

I assembled the mold and made sure the foal was in there with a tight fit. I then placed the rebar mesh down. Next i spent HOURS poking the fiber optic cables into the foam. I decided to go with 11 different sections (I was limited by the number of LEDs i had with an older setup that was much more intense and did not use the individually addressable strips). I made 11 bundles of the fiber optics and divided the full length of the bar in to 11 sections that were about 6.5" wide. I tried to be random yet somewhat even with the distribution of the cables.

It is kinda hard to see in the pictures but I also added some foam inserts for where the bar mats would be 'embedded' in the top of the bar.

Step 3: Mix and Pour Concrete

I decided to make the first layer (will be the top of the bar) a little wetter and darker than the rest. I mixed the concrete dye with the water and mixed all of that together in the mixing tub. I was very careful to make sure that the concrete was applied evenly throughout the mold paying extra attention to the spaces in-between the fibers.

I let the concrete cure for several hours after applying this first layer that was a little less than 1" thick. I shook the table (lifting it up a little bit and letting it slam down) every 10-20 minutes to try to get out as much bubbles as possible.

Once the first layer was cured I added the rest of the concrete mix until it was at the appropriate thickness. I believe I needed almost two full 80lb bags. I covered the whole thing with a plastic sheet and let it cure for a full week. I am not sure how long it really took to cure but I was only able to work on this over the weekends and it was definitely fully cured by the 6th day.

If I do this project again i would look into getting or making some sort of concrete vibrator. I got a lot of the air bubbles out of the surface but there are still a few and it would be a lot nicer if it were perfectly smooth.

Step 4: Build the Base (pedestal)

This part can be its own instructable so I will just gloss over this part. I overbuild everything I make and this is no exception. Since the bar top is about 160lbs I made a super sturdy base out of 2x4s. I live in Chicago and move apartments every year or so which means I need a free floating bar. I made a pretty giant base out of 2x4s and 3/4" plywood/subfloor. I wanted to make sure that the thing would never fall over and crush someone (knock on wood) so there are counter weights in the back of the base to help stabilize the pedestal.

The whole bar is in 3 big parts. The top is bolted to a piece of plywood and has a little 2x4 skirt around its base. Then the pedestal (the vertical part) is one piece that bolts into the top and base. The base is one giant 'stage' looking thing that the pedestal slides into.

At the time I could not find corrugated metal for a decent price so i bought the cheap plastic and spray painted it metallic gray. Since then I was able to find some real metal and applied that to the pedestal instead.

Step 5: Set Up the Fiber Optics and LEDs

Again, this should be its own Instrucatble. I 3d printed a little two part bracket to keep all the fiber optics in order and bundled in the right place for the LED strip. I used an Arduino Uno, individually addressable RGB LEDs and the FastLED library to program the strip. I had to follow many YouTube tutorials and a few instructables to get this to work so I am by no means an authority on this part.

Step 6: Put Out Tip Jar and Enjoy the Light Show!

I actually plan on completely redoing this project in the next year. This was my first concrete project and my first fiber optic project. I learned a lot of things along the way that will make the next one cooler, easier, and hopefully lighter!

Thanks for reading my very first ever Indestructible! I submitted this very rushed and last minute because I saw the concrete competition. If you liked this (despite its many flaws and incompleteness) please give it a vote!

Stone Concrete and Cement Contest

Participated in the
Stone Concrete and Cement Contest