Mercy 

The reason I decided to go with Mercy as my next big build was because I wanted to make something animatronic, but larger in scale than my previous projects.

This particular version, the early concept art from The Art of Overwatch book, although visually striking, to my knowledge was not cosplayed by anyone before, so I was eager to ‘go in blind’ with no other references than that single drawing.

The project was challenging, and made me learn loads of new skills:

• I never worked with aluminium before, so I had to buy a welding machine and learn how to weld.
• I haven’t done 3D modelling, so had to learn some of that too.
• Using unusual electronic components – f.x. Chip on Board LEDs and how to animate them.

Because of that, from start to finish this entire build took around 1,5 years.

Materials used in this project: aluminium, steel, plexiglass, pleather, EVA foam, PLA 3D print filament.

Techniques used: welding, soldering, 3D modelling, 3D printing, sewing,
foam-smithing, painting, airbrushing.

I chose metal as my primary material. Although it is really hard to work with, it has a distinct, “real” look and feel to it that I wanted for my build.

I. Wing Mechanics

Animatronic wing designs usually have just a single moving ‘forearm’, so I had to come up with my own mechanism that would extend all three ‘wing blades’ at different rates, while using the same single motor. I got inspiration for it form a mechanical watch.

One of my goals was to make wings feel agile and “realistic”, so I decided to add another axis of motion which complicated things considerably. The wings could not only rise, but spread too, but that meant that all the weight would rest on these ‘spreading motors’. (The range of motion is defined by limit switches.)

The back brace at first was a flat sheet of 3mm aluminium, but then I redesigned and hammered out a curved, lower back hugging version out of 4mm aluminium, reinforced with steel.

For improved stability, I added a waist strap to avoid swinging, since the entire rig is so top heavy + there’s a lot of momentum once it’s in motion.

All 4 motors – 2 ‘spreading’ + 2 elevating ones are based on worm-drive gearboxes – means they are fixed in place when unpowered – great for battery life, and convention safety.

Speaking of conventions – I designed all  arts of the cosplay in such a way that when disassembled, all fit in a standard size  suitcase.

For quick, toolless assembly I made quick release mechanisms for each wing blade out of IKEA cabinet door hinges (this way  anyone can help me get in and out of cosplay in a couple of minutes, no tools needed)

All covers are fastened magnetically for quick suit-up/repairs.

(Connections for wing blades are color-coded for correct LED animations)

Pretty much everything is made out of aluminium and steel – total weight is
about 25kg (~55lbs).

It was a real challenge to have this much mass move this quick (sluggish animatronics are worse than none). The motors were struggling, so I had cut weight by sanding down around 400g of aluminium off of wing blade surfaces by hand…

This reduced the total mass, and made the wing profile much more sleek. Subsequent polishing to a mirror finish took around 4 weeks.

The wings still turned out way heavier than I predicted, so I needed to re-make/reinforce other parts as well:

To etch in the decorative details on the aluminium surfaces I used a vinyl stencil and a brass wire wheel:

I used a blowtorch to heat-discolorate the wing-stems for authenticity, to make them ‘functional’-looking, as if they get hot during operation.

II. Electronics

The entire costume is powered by a single 4 cell LiPo pack, which is split into 3 power rails.

– 5V is powering the Arduino.
– 12V is powering the MOSFETs that animate the LEDs (more on that later)
– 15V is powering Motor Drivers (even though the motors are 12V) to provide extra torque needed to move such heavy loads, in the expense of their lifespan.

The Arduino is responsible both for LED animation and the motor control. I made a ‘mother’ circuitboard for it, so it is quickly swappable (convention day panic-repairs are the worst).

Motors are controlled by a PSP-style joystick in my right glove. X-axis for spreading, Y-axis for elevating the wings.

The LEDs were the by far trickiest part of electronics. I wanted my costume to be extra bright (something regular LED strips just couldn’t do). Furthermore, I didn’t want any spotty light, which in my opinion is the ultimate immersion-killer. I went with Chip-on-Board LEDs, which are soldered to an aluminium substrate/heatsink.

They get very hot, are stiff and fragile, have bad color uniformity, and only come in set lengths (in modules). 
BUT they get bright, and they glow smooth.

I bought about 3-4 times as many LEDs as I ended up using because they’re so fragile, that I broke many of them trying to curve   hem along the
plexiglass wing edge.

Since I needed multiple modules per wing (meaning they’re very close to each other), any color variance between them was very noticeable.

I had to just keep buying LED modules until I got enough units with the approximately desired color temperature. Then I used very high grit sandpaper to carefully sand the factory added color correcting top-layer, to dial in the LEDs to the exact same shade of white.

The result is color-accurate and bright wings (all the way to the tip!):

You can’t animate these LEDs like Neopixels or LED strips – so I had to make my own, high current MOSFET-based ‘animation’ board, controlled by the Arduino.
The LEDs are divided into 4 groups:

Wing Caps (+ Halo), Top Blades, Middle Blades and Bottom Blades. By manipulating their brightness over time I am able to perform basic animations.

III. Halo

The halo is also made out of plexiglass, sanded to a taper, and edge-lit (like the wings) with the same kind of LEDs for a consistent look.

It is mounted on a steel ‘invisible mount’ of my own design, that is further hidden behind the costume’s neck cover.

IV. Battle-Staff

I made it out of 3D printed parts, PVC tubes, and aluminium sheet-metal plating.

It is also animatronic – it’s head rotates with the help of a tiny motor hidden in the body of the staff.

It’s modular for easy transport. I also added a little Overwatch logo as an easter-egg.

I painted it with spray-paint, airbrush paint and weathered it with Rub ’n Buff.

V. Armor

Made out of 10mm and 5mm EVA foam, fastened with velcro.

Boots + shoes primed with PlastiDip, thigh armor – with wood glue.
Everything airbrushed, edges weathered with Rub ’n Buff, blackwashed with acrylic paint.
Glossy top coat on thigh armor with Valejo Airbrush Varnish for candied-apple look.

VI. Jacket

Made from pleather, racing suit-style mesh armpits for breathability. Dual zipper design (to fit over wing harness). Embroidered details.

Little Easter Egg – my initials inside the neck-buckle.