Introduction: Arc Reactor a La Smogdog, a Very Personal Project…

About: Hi! My name is Hans, I live in Scandinavia where I build whatever pops up in my head, out on to my sketchbook and finally into my hands. My projects here are my favorites and I hope some might inspire you. Rem…

What do I have in common with these two guys? It's not the beard this time!
We've all got a hole in our chest, well me and Leo were born with Pectus Excavatum, Stark had to earn his:-)

Pectus Excavatum is (look it up here: a dent in my chest, they come in all sizes. I've never minded my odd chest, but rather made use of it (I tell kids I worked at a circus but had to stop after being step on by a baby elephant who stumbled in an act:-)

Turns out I found a new great use for this chest dent… I can fit an arc reactor in there!

Shout out to Laura Kampf for her "Every Defect Gets Respect"… Perfect is sooooooo boring!


Sugru silicone mold (

PLA filament for 3D printing (and some PETG clear filament)


Kitronic NeoPixel

LiPO 503035 500mAh 3.7V (2X3V coin batteries were used in the first version)

Small on/off switch

2X3mm (switch) screws & 2X4mm (Neopixel)

9V battery

Touch on/off switch

Step 1: So How Big Is It?

Even though I've had this for my entire life, I don't have a full grasp of its size so I made a Sugru mold. 3 packs were enough and then it was time for fitting. Didn't leave this in overnight, I had it there for a while so it would keep its shape.

Sugru is great for prototyping!

Step 2: 3D Me…

Now it luckily turns out I work at a place where there is a 3D scanner and students willing to help a wannabe Tony Stark. So one day my chest was scanned and with a little help cleaning up the 3D mess made a perfect representation of my dent.

I quickly made a first attempt in Fusion 360 so I could make a test print:-)

Step 3: In the Making…

As my process is always mistake-ridden, I know there has got to be a version 1, 2, and 3, often more. This build was close to that road map. By doing the first version based on a Sugru mold I knew I had room in my chest for a Micro:Bit, a battery, and a LED ring. So as soon as I got the 3D file from my chest scan I printed a quick test of the base that would later ft in my chest. I went too big, but from version 3 and onwards I had found the right size.

Then I could focus on the details within the base.

Step 4: Programming the MicroBit

I really enjoy the MicroBit for its simplicity. For now, I only have a pulsing light. I will spend some time and add some more options, with pulsing, moving, blinking, and much more.

Step 5: Print Test No. 3…

Now that I had nailed the size I could start test-printing the final version.

I've found printing almost anything at a 45-degree angle will benefit the print quality and require less support. The details within the mount were important, especially the threads, 3mm for mounting the switch, and 4mm for the LED ring with the Micro:Bit attached.

Also getting the right infill so it would not be too heavy and fall out.

Step 6: Power Station

With limited space, I decided to test how coin batteries would function and if they could fit. I made the battery connectors from some copper tape I had and soldered the wires to each piece of circle cut copper tape. This worked fine, but the downside was that I would need to pull them out when they run out of juice.

Step 7: Power Up the Arc Reactor

For this test… I had the best T-Shirt :-)

Step 8: Details, Details, Details…

This is it, will it all fit? Spoiler… it did:-) I made it so it would be easy to recharge the batteries and as you can see a way to plug in the Micro:Bit for loading new code.

I also went for some details that won't be visable when everything is mounted, but knowing they are there makes me so happy.

Smogdog, arc symbol and an arrow to show which way is up were all in place.

Step 9: But Wait… One More Thing…

My builds are never complete if there is no box to hold/protect the build! Giving a little more allure and finesse to this creation I made a simple wooden box. I won't go into detail of the box construction you'll see in the following images on how it was made to work.

I wanted the Arc Reactor to be kept safe when not in use and also give the opening of the box a wow-effect.

So I first off designed a base, printed it in clear PETG for the light to glow through.

Step 10: Mechanical Motion

When opening the box I wanted the base to move out and light up automatically. I did this by using two leather bands attached to the inside of each lid. I cut cushioning to fit the inside for protective measures.

Step 11: It's All About the Base…

The 3D printed base is fastened to a wooden plate velcro for easy access.

When the base is lowered as the lids close the button in the box turns off the light. The LED strip is powered by a 9V battery. The effect is really cool and I love how it turns on as you open the box.

Step 12: Handle It

For the closure to work and still be able to use a handle I cut the handle in two. I found a metal pipe that fit with enough wiggle room so it wouldn't be difficult to attach the two sides. A magnet keeps the handles locked.

Step 13: Always Think Inside the Box!

I think making this box made the project so much more rewarding. As Mr. Savage says, boxes are vessels for storytelling. The curiosity of what hides inside is amplified with the stamps, giving hints at what might be inside.

So one question remains… what will I use this Arc Reactor for?

I will, this fall use it while giving a lecture to my students add some new energy to the room and myself by activating the Arc Reactor when all air is gone in the room:-D

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