FireStorm Matrix
A 3D printed wearable prop with LEDs
Intro
A wearable, LED-lit chest piece based on Firestorm from The Flash. Modeled in Fusion 360 with sewn and Velcro-mounted components, it used NeoPixels and off-the-shelf Arduino code. Hand-soldered and 3D-printed, it still works years later—though today, I’d swap the wiring for a custom PCB.
Concept Origin
This was one of the first projects I actually bothered to document (outside of professional work), and also the first time I ever cosplayed. The character was Firestorm from the CW show _The Flash_. I don’t remember many plot details, but I _do_ remember he had a really cool, glowing, mechanical-looking chest piece. It looked complex enough to be interesting and just plausible enough that I thought—yep, I could make that.
Design & Development
CAD Modeling
By this point, I had a few years of CAD modeling experience under my belt, so this wasn’t too challenging just fun. The design is fairly simple in form, but layered with secondary and tertiary shapes to make it feel more complex and “real.” I modeled it in Fusion 360, which was still relatively new to me at the time.
A couple practical challenges showed up early:
How to wire all the LEDs
How to actually attach the whole thing to a jacket
The character’s “matrix” includes a big chest piece and several glowing satellite units that connect around it. The tricky part? All these rigid components need to mount to a non-rigid jacket… _and_ several of them cross the zipper. Which means: they need to be removable.
Design Challenges & Mounting
To solve that, I added channels into the 3D model so I could sew the main unit directly onto the jacket. That central piece held most of the weight and wiring complexity, so once I locked that in, the rest followed.
Power came in through the central unit. I tucked a small USB battery bank into one of the jacket’s inside pockets and wired it directly to the back of the chest piece. Worked great.
As for the satellites:
Some were sewn directly on
The ones that crossed the zipper were attached with Velcro for easy removal
Electronics
Electrically, I was 100% a beginner at this stage. I leaned heavily on Adafruit tutorials and modules. The setup was pretty simple:
A NeoPixel ring + microcontroller in the center
A single NeoPixel in each satellite unit
Each satellite had 4 wires running back to the center (yep... four)
Everything was wired in series because I didn’t know a better way. That meant a lot of extra soldering, but hey—it worked and held up well. The fire effect was just an off-the-shelf Arduino LED sketch I found online. Pretty sure it was called "Fire2012" or something like that.
Prototype & Build
Even though this was my first cosplay, it wasn’t my first 3D-printed and painted object meant for public viewing. So I followed the usual steps:
Sanding
More sanding
Filler primer
You guessed it - more sanding
The goal is to smooth everything out so it doesn’t _look_ 3D printed. Once I got to a good surface finish, I slowly built up thin coats of paint until it looked the part.
Since a lot of parts had to fit together precisely, I had to be extra careful not to overpaint contact areas or rush dry-fitting.
I also bought a few real metal parts, aluminum and brass, for added shine, which I glued into place.
The Clear Domes
This project had several large clear orbs. I printed those in clear resin on a Form 3, then wet-sanded and polished them smooth. For final clarity, I added a thin coat of clear spray, which made them almost glass-like.
Once everything was painted and assembled, I started the (very delicate) process of soldering all the electronics into this now very not-easy-to-disassemble prop. Thankfully, I’d already tested the wiring outside the unit, so there weren’t any surprises just lots of careful routing.
Final Result
Honestly? I think I did a pretty solid job for where I was at the time. The battery lasts several hours since it’s just a few LEDs at medium brightness. I still have the jacket, and it still works like the day I built it.
Was the character too obscure? Yeah, probably. At NY Comic Con, only one person correctly guessed Firestorm. A few dozen others had fun guesses, though.
Still, I love making props with lights or interactive elements. People _love_ glowing stuff. Shiny = dopamine.
Reflections
This build is several years old now, and the jacket's still holding up. A few of the tiny pieces from the satellite units have broken, but honestly, that’s not bad for something that’s been to two cons.
If I made this today, I’d absolutely change a few things:
I’m much more comfortable with electronics and would design a proper PCB
I’d ditch all the hand-soldered mess for an adapter board with connectors
That alone would make assembly cleaner _and_ make the design shareable
I also think I got a little too obsessed with realism trying to imagine how the real prop would have worked or been assembled. I burned a lot of time trying to be clever about painting and mounting when, honestly, simpler would’ve been better.
