Back in January 2020, during the weekend of LoveLive Fes at Saitama Super Arena, I was struck with the idea of constructing the mask of one of the characters, Tennoji Rina, of the idol group Nijigasaki School Idol Club. It would make for a great cosplay set piece and a fun challenge to construct.

According to character lore, the mask itself, called the “Automatic Emotion Conversion Rina-chan Board”[ オートエモーションコンバート璃奈ちゃんボード] was developed by the computer department of the fictional school in order to assist Rina in expressing emotion. It is theorised that she is on the spectrum and struggles to express emotion, and thus the mask was born to help her do so.

During that cold weekend in the middle of January, Tanaka Chiemi, the actress who plays the role of Rina, entered the stage at Super Arena wearing the mask, and it was impressive.

It was very well polished, with what appeared to be frosted Perspex plastic on the front face to hide the LEDs behind. Obviously, without the support of a large conglomerate to fund my exploits, I would have to rely on the knowledge and ability I have, while researching new methods. Frosted Perspex could be an option for hiding any grid line the LEDs may create.

While researching and sketching up initial designs, I ran into an acquaintance who just so happened to have the same idea, but was already leagues ahead of me. While I really wanted to design my own mask from the beginning (It’s exciting!), I knew that the time spent could be used on other projects, so I reached out to my friend and they were more than happy to share their current work with me.

While discussing electronic configuration, Arduino code, LED setups and programming, we both discovered that a Japanese fan had already engineered his own mask and provided the mock up designs for the electronics on a handy blog post. He also had created a video on YouTube, displaying his work.

Requirements - https://qiita.com/hamahamabe/items/9216df345bb908eb5199

Design - https://qiita.com/hamahamabe/items/f2a5497aea395eb9699d

Programing - https://qiita.com/hamahamabe/items/6612540a72b915410b99

For someone who claimed they were an absolute beginner at 3D printing, design and soldering, Hamato did an excellent job and is a great example of accomplishing great things when you put your mind to it. There are some improvements that could be made to the electronic, such as

Hamato didn’t provide 3D designs (for good, legal reasons), but did provide great notes on LEDs with measurements included for the front face. With this information, it was easy to mock up potential faces on grid paper.

Hamato recommended these LED strips for the face in his blog posts, so rather than reinvent the wheel, I’ll make the trip over to Akihabara for these.

https://www.akiba-led.jp/product/1772

Finally, here are some pictures of the 3D parts to be printed on an FDM printer. Some parts are almost 200mm large, taking up all the space of a standard, run of the mill FDM 3D printer.

-=Parts List to be acquired=-

Arduino Nano (preferably Arduino Due for scalability)

3 x Switches (at least)

5V1A Battery Pack (at least) (Nano/Uno cannot go higher than 5.5V)

NeoPixel 2020 Extra Fine Tape LED 1m / 120LED [ 9779 ]

Breadboard Jumper Kit (for good measure and testing)

Transistors

Stay tuned for the next post. Up next is 3D Printing!

For legal reasons, these 3D models will not be available to download.

Due to currently only having immediate access to an SLA 3D Printer, this project has been put on hold for the time being until a suitable FDM 3D Printer is acquired.