Princess Serenity (Sailor Moon) Cosplay Light Up Dress - Part I

I'm a strong believer in quality over quantity, which is why I'm a one-cosplay-a-year kind of gal.  I knew I wanted more electronics in my next project, but was lacking inspiration. Then I saw the piece of Sailor Moon fan art.

 I was captivated by the color in it. I knew what I wanted: to recreate those soft hues in lights.  I was also inspired to flip it thanks to this piece of fan art by Keah. It took six months from concept to completion. Here's where I ended up (view the rest on my DeviantArt page):

This is a three part series of how I constructed my Sailor Moon Crystal Princess Serenity Light Up Dress Cosplay.
Part I - The Dress
Part II - The Sleeves
Part III - The Overlay and Accessories (Coming Soon)

What was your dress pattern?

The good news is that Serenity's dress is a very simple pattern. The bad news is I was struggling to find a version with minimum modifications. Lucky for me Sailor Crafty has a great article on how she made her NeoQueen Serenity dress that includes her pattern number.  THANK YOU!

NeoQueen Serenity's dress is more of a silhouette than Princess Serenity's empire waist ballgown, so I added two panels up front to give it flow. The train in the back is cut short to keep my lights off the floor. Also, I bet I would trip a bunch on it.

The triangles were my two additional panels

The fabric is a heavier weight, non-stretch cotton to help support the weight of the lights. Admittedly, I was still working on those logistics but I knew light fabric would likely sag in the wrong places.

What lights did you use?

I had two guiding principles for this cosplay:
1) It must good with the lights on or off
2) The lights must be visible in daylight and evening

Principle number one is a topic for part III. Principle number two meant a lot of light tests. My first thought was NeoPixels by AdaFruit.  I ordered a Gemma starter pack to play with the lights.

The NeoPixels were amazing! They are bright! They can be any color! They are easy to program! But they are expensive and they can be hot to the touch. I needed something requiring less money and skill.

Left side:fairy light test; Right side: Neopixel test

Christmas lights! That's cheap and already on a string! Amazon yielded few results for battery powered christmas lights but they did have lots of 'fairy lights'. They're small LED lights on copper wire and often are battery powered. I ordered a pack to test -- Winner!

Typical 'fairy lights' - 7-10ft with a battery pack

The lower dress is composed of 28 feet of led lights - 14 ft blue and 14ft of purple. Total light cost was under $30.
I did have to solder together 2 packs of each lights and redo the solder points already on the strand. All solder points were coated in clear nail polish to prevent shorts from the wires touching. The light strings were soldered to an AdaFruit Gemma to regulate voltage  and provide an on/off switch. (Yes, a gemma is overkill for those functions. No, I don't care because it was simple.)

Light repairs with the help of my dad.
I used alligator clips for a very long time to make sure everything was right. 

How did you get the lights in the dress?

I flipped the fan art to have the lights 'trickling down' from the middle of the dress and exploding at the bottom. The new design would allow for me to load batteries at the bottom of the dress for easier placement and access while I'm in it.

 I laid out the bottom half and sketched my lights outline with a fabric pen. Then I pinned the final lines I liked the most.

The right side shows where I sketched my light lines.
The left is the first string of blue lights pulled through. 

Electronics are fickle. If I sewed the lights on, I would have to remove and restitch every time there was an issue. (There were a lot of issues at first). The solution was a combination of fabric tubes and ribbon that I could run the lights through. I used tubes for the first line to hold the lights up, then progressed to ribbon hooks for lower levels, and ended with sheer ribbon for the very bottom.

Unlit dress showing the light support system.

The purple lights are the ones encased in shear ribbon. Being on the bottom, I was afraid of snag and wanted to protect them more. The ribbon does it job perfectly but it was very difficult to string the lights through because I didn't provide enough gaps to pull the lights.

Two strings of lights in!

All the lights in and on!

Where did you hide the power for all this?
Like I mentioned above, the light strings were soldered to an AdaFruit Gemma to regulate voltage to 3volts and provide an on/off switch. Here's what that looks like sewn into the dress.

The velcro is the strip of fabric I use to cover and protect the gemma. By having all the wires hook up to this one gemma, I can connect a battery via jst or a micro-usb. The battery pack sits in the pouch sewn in below the gemma. 

I purchased a li-poly 2500mAh battery on my favorite site for power. 

And the rest of the dress....?
The rest is very straightforward. I sewed the top and the lining according to the directions. I did add more boning than the original pattern (six pieces instead of four) to prevent the front from collapsing. The real story for the rest of the dress comes in part III where I cover the beading and chiffon overlay.

Dress base complete!

What issues would you avoid your second time?
I spent two months researching and testing before I started to build. That wasn't an issue, but not needing that much R&D would make this project go faster!

I would use more fabric tubes and less ribbon to support my lights. I had enough dress scrap to make more, yet I hesitated to cut it in case I made a bigger oops.

The top of the dress kept concaving in after I placed all the beads on. My sister*, a textiles major, quickly pointed out I needed more boning. I wish I placed that additional boning in before I did beading and my liner.

My lights kept shorting at the start, which was really frustrating. My dad*, an electrical engineer, quickly pointed out that my wires at the solder points were touching and causing the short. Clear nailpolish is working, but I wish I had smaller heat shrink.

*Never underestimate the good advice of friends and family when working on a cosplay, regardless of their cosplay level or participation.

Final dress with lights on, minus the chiffon overlay.

Thanks for your interest! Don't forget to come back for parts II and III for the rest of build!