Introduction: Arkenstone Display Using Arduino Esplora

This is a tutorial for making an Arkenstone Display that utilizes an Arduino Esplora. This was done as an assignment for CS 4985 Rapid Prototyping. In order to make this easier to understand, I will break this up into 3 parts: code, stone, and chest. Please bear in mind this will show my first attempts at casting resin and wood staining. Also, I apologize in advance for my poor photography (shaky hands, ya know?)

You will need:

a mold (more about that later)

Arduino code (will be attached)

Alumilite Amazing Clear Cast epoxy resin

Alumilite Amazing mold putty

an unfinished wood chest/box

2 small blocks of green floral Styrofoam

mold release spray


wood stain

polyurethane coating for wood stain


clear nail polish


power source for Arduino (more about that later)

Neopixel Ring (12" or has 16 lights)

power source for ring

Step 1: Part 1: Code

The code for this assignment was a simple idea: lights that rotate around a Neopixel ring. I wrote it so that the light progressed around the ring and grew brighter as it moved. I added functionality so that pressing the up, right, or left buttons would cause the color to change from base white to either green, cyan (light blue), or yellow. To finish the code, I added functionality so that moving the Arduino's potentiometer or slider bar, would increase/decrease the speed. All the way to the right is the slowest setting. Please note, halfway through coding I realized that having the lowest set to 0 made the lights move so fast that it could cause a seizure. I mapped my values to between 500 and 30 as opposed to 1023 and 0. Changing this is relatively simple and I have attached the program if you wish to use/tinker with it.

Step 2: Part 2: the Stone

Ah, the Arkenstone, the glorious gem of Hobbit fame from Erebor. I tried 3 times to create it in resin and now I will let you know how that worked out.

First, I created a mold using SketchUp. The basic idea is to draw 3 overlapping hexagons, with the middle one angled slightly differently than the outer two. Then use lines to connect the hexagon corners and use the Move tool to pull it up, a layer at a time, along the blue axis. Here is where I found the steps to do this process if I wasn't clear enough. However, Solid Inspector, the SketchUp extension that I use to make sure that all my objects are solid decided to fuss. So, after much thought and playing around I fixed the problem. First, I sealed the open circle at the bottom of my mold. The I used the extruder tool to pull that circle up over my gem until I hole was revealed. After saving it as a .stl file so I could make it into a .thing file for the printer, I 3D printed it on our university's MakerBot replicator. I did scale the mold in the stl file 61% so it was the proper size. Attached are 2 in progress shots, the skp file for the mold, and the stl file as well.

Next, it was mold prep time. I used some woodfiller and sandpaper to get the surface of my mold ready. I then rubbed on a layer of Vaseline so it wouldn't stick. I then prepared my resin as per the instructions for the Alumilite Amazing Clear Cast epoxy resin. I poured my resin then waited 24 hours for it to cure. Here's the rub: it never would come out. I even had my Dad use his hammer and a chisel to it - the plastic came off, but most of it clung to the stone. I tried again using a mold I printed at my Dad's drafting lab, a coating of resin on the mold, mold release spray, then a second resin casting. Still, the mold would not give up its treasure. I couldn't even chisel off the mold this time! Finally, I hit the craft store again for some Alumilite mold putty. Using one of my sister's paper weight/glass gem, I cast a new mold. Why not use the paperweight? One it wasn't flat at the bottom like I needed and 2 it was really heavy. Finally, I had an Arkenstone- a misshapen, bubble riddled Arkenstone, but a stone nonetheless. At this point it was the Monday before this was due so I had no more time for recasting or I would have tried to fix it.

For the last step, I cleaned of my stone (the silicone mold left some residue) then applied clear nail polish on the back to get rid of a sticky residue (probably due to poorly mixed resin or humidity). Now, my stone was ready.

Step 3: Part 3: the Chest

Okay, first I took my unfinished box and stained it using some Min Wax wood stain in a Dark Walnut color. Once that had dried, I coated it with the polyurethane coat/gloss. This was drying while I was working/fighting my resin.

Once all the pieces were ready, it was time to assemble. First my Arduino, my usb power source, and my Neopixel ring. The ring had a power source (battery pack) soldered to it. Next I decided on arrangement. Then I took my two blocks of floral Styrofoam and cut them down to the right size. I then made a small hole all the way down for the light to show through. I followed it with a slight hole on top that was for the stone to sit upon. I made an image of the inside of chest thus far.

I cut some red scrap fabric for the covering and placed it thusly on the Styrofoam. I then covered up my hardware, placed the stone, and VOILA! An Arkenstone display powered by an Arduino Esplora!

Final note, I could not get my power source to last for more than a few seconds at a time. In order to fix this, I made it so that I could reach my power supply's reset button so I could keep the lights working for as long as I needed. Unfortunately, resetting also resets the color, but's that a minor bug in my opinion. I hope you enjoyed this tutorial and that it inspires you to go on your own crafting adventures.