Wearable Iron Man Arc Reactor

My name is Jack Monaco, but, like many people, I think it would be pretty cool if I was Iron Man.

Every year at my school we have a week of rallying and class spirit competitions, and each day of this week has a dress theme, the first of which is character day. Being a maker, I tend to go all out on this day and put a lot of effort into my costume pieces, and this year I decided to entertain my Iron Man fantasies and dress up as Tony Stark. So, with just about a week and a half to work on it, I began the process of making a working Iron Man Arc Reactor.

The video above gives a good overview of the process and I would encourage you to watch it. This Instructable will just go into more detail than what is covered in the video.

Step 1: The Design

After a bunch of research I ended coming up with my own design for this build. I wanted a relatively realistic reactor that could be worn both inside and outside of my shirt. This necessitated a design that was completely self-contained.

The general idea was that the reactor would be lit by two rings of LEDs, an outer and an inner. Power would come from a stack of 4, 3-volt batteries in the center of the unit. All the power and electronics would be housed inside a puck-like piece behind all the aesthetic details. I would then have some sort of harness to wear underneath my shirt that the puck would sit into. To be worn more visibly the puck would be pressed into the harness from the outside to sandwich the shirt material and hold it in place.

It was also established pretty quickly that 3D-printing would be necessary to fabricate all the parts that I had envisioned for the design, so if you plan on attempting this project, you will definitely need access to a printer. All the stl files for the pieces that I modeled for this build will be linked in this Instructable.

Step 2: The Main Light Ring

I started by modeling the main ring in which the outer string of LEDs would be housed. I got outside dimensions from the Replica Prop Forum, and I modeled a ring with square channels cut into the sides for the wire wraps and a main channel for a strip of LEDs. I printed the model in orange just to check how it felt. This design seemed fine, so I printed it again in clear PLA. The problem that this model seemed to have was that, it being clear (or at least translucent), the light highlighted the gridded printing structure inside it, which did not fit the look. To solve this issue I remodeled the piece with thinner walls and printed with 100% fill. This also provided more room for the light to bounce around and allowed it to shine through clearer.

The lights for this build are cut from a strip of self-adhesive LEDs that can be cut off and soldered to at custom lengths. They are very bright and require 12 volts of power. I cut a strip of these LEDs and soldered a pair of wires to the end. I stuck the strip to the wall of the channel in the main ring and hooked it up to a power source to make sure that the connections were good. Once the wire wraps go on the electronics are trapped, so I had to make sure we wouldn’t have any problems. With a little extra hot glue for security, the main ring was ready for the signature arc reactor wire coils.

Step 3: The Wire Coils

Tony Stark's arc reactor has 10 coils of wire spaced around the ring. I achieved this look by modeling small U-shaped pieces that would sit in the square channels that I had modeling in the main ring. The wire would then be wrapped around this piece and kept in line by some small walls. After several versions I got this piece to fit snugly onto the ring. When the model was perfected I printed ten of them in gray PLA and slipped them into place. I began wrapping with a red-ish colored 18-gauge copper wire. I would hook one end of the wire on the edge of the channel in the main ring and then wrap around the gray piece seven times, after which I would cut it off and crimp the end around the edge again. This proved time consuming and tricky, but the final ring looks fantastic and the wraps do a good job of blocking the light from the LEDs.

Step 4: I Got the Power

Now we approached the issue of powering this little device. My plan had been to use a stack of four 3-volt CR1616 batteries to provide the 12 volts that the LEDs need. But, when we plugged the LEDs into an Ammeter we found out that our lights were pulling about 3.8 milliamps per LED. Each CR1616 only has about 60 milliamp hours, so with 36 LEDs, the four batteries would only give us bright light for about an hour. Since this was not ideal, we decided to move up to using CR2032s which would give us a total of at least 4 hours of good light per set.

The CR2032s were an ideal solution to the power problem, but it meant that we now had to accommodate larger batteries into the design.

Step 5: The Housing and Extra Wiring

I modeled a puck-like housing unit that would fit the light ring snugly. It has an inner cavity for batteries and a wire, as well as a space for the existing wires to come through. The inner LED ring will also be attached to the wall of this cavity. There are also some structural pieces to protect these inner LEDs and some wings to hold the remaining aesthetic pieces. The first version of this housing warped, and I ended up printing the second one with less structure to help light get out more. The pictures are of the final model and print.

Before installing the main light ring I soldered the second strip of lights and wrapped up the connections. At the end of the second strip I soldered two final wires. When these wires were hooked up to the battery stack, the circuit would be complete and light up.

The main ring fit into the puck beautifully. I protected the soldered connections again with hot glue and attached the inner strip of lights to the wall of the battery cavity. The positive wire I coiled at the bottom of the battery cavity, and the negative I routed up and over to a small grove that I had modeled into one of the walls. Now to complete the circuit the negative tip of this wire just needed to be connected to the top of the battery stack. This would be accomplished through the centerpiece of the reactor.

Step 6: The Centerpiece

I modeled a clear piece that could fit in over the existing structure in the housing piece. I attached a wire coil to the underside of this piece that comes into contact with the negative tip when you rotate the piece in place. This proved a pretty effective method for turning the reactor on and off. This piece needed more decoration, so I modeled some other decorative pieces and added a wire ring in the center.

The rest of the details on the reactor piece were purely aesthetic, but really make the look. I coiled some more copper wire around a pen cartridge and glued these coils into the back of the cavity. I also printed a circular, slotted piece in black which sat on the wings of the housing piece.

With this the arc reactor puck was complete! Now it just needed to be attached to my chest.

Step 7: The "Harness"

The concept for having the reactor be wearable both inside and outside the shirt included a sort of harness that would strap around my chest and neck and hold a cup in the center that the puck would either sit in underneath the shirt, or be pressed into through the shirt. I modeled this center cup with four square clipping points. I also modeled the other halves of the clips that could have elastic bands sewn to them.

The main part of the harness was at first too small to fit both the shirt and reactor, but by making the cavity bigger and adding some duct tape around the inner edge it was a perfect fit for both the shirt and reactor.

I then sewed elastic bands to my clips. I got some help measuring my torso and sewed these bands together. My “harness” soon came to be appropriately nicknamed “the Iron Bra”. So if it helps you to conceptualize it, it's a racerback...

At this point I was finally ready to put it on.

Step 8: Feeling Like a Boss

The title says it all... this thing is awesome.

This project took a lot of work and time, mainly because I came up with an original design concept and modeled all the parts myself. As you can see this project is also HEAVILY reliant on a 3D-printer, and anyone with 3D-printing experience knows that there is going to be a lot of trial and error involved with a project including 22 3D-printed parts. So that you do not have to endure the trial and error process of this project, all the part files for each step in this Instructable are attached.

If you are curious, I modeled all the parts for the reactor in SketchUp. This program works great for geometric pieces such as these, but I did find it most accurate to model all these parts at 10X the size and then shrink them down before printing.

In the end, my only complaint about the design is that I wish the centerpiece fit into the unit better. It tends to pop out and break the connection. I fixed this temporarily by adding some duct tape for extra grip, but if I did it again I would try to model the piece and the housing to actually snap together. That being said, I was overwhelmingly happy with this project’s result. Not only did the arc reactor attract a lot of admiration at school, but it remains a great fall-back costume for events, and has also helped me to feel like a boss during power outages. I would definitely recommend trying this project out next time you need a memorable costume, so let me know if you have any questions :)

Happy making!