Megabot, destroy!

Lilo wasn’t my only cosplay for Dragon Con. I always have high expectations for myself, even if something’s a totally new experience for me. Hobbies are no exception.

Now, for those of you that don’t personally know me, I LOVE Disney (like, live and breathe). I think about hopping on a plane to Disney World daily; I’ve had many-a-daydream about being a Disney princess; I even go so far as to play Disney music while I’m on shift at the MakerWorks (MIT’s new MechE makerspace!) while machining and the occasional (shop-safe) frolicking. Anyway, my other cosplay idea became obvious right away. I am a bot-fighter, and the world was recently introduced to a Disney bot-fighter. I must be Hiro, and with some of my other bot-fighting friends, we could be a pretty good Big Hero 6 crew (pictured below). The height differences even almost work out!

From left to right: Cynthia Lu/Lushan (Baymax), Jamison Go/The Variable Constant (Tadashi), me (Hiro), Hanna Lin/Hannalopolis (Gogo), Dane Kouttron/Transistor Man (Professor Callaghan).

Big Hero 6

Now, just dressing as Hiro was too easy, and I wanted to incorporate a maker-component. I had initially thought of 3D printing a bunch of little microbots on strings, but it would be a difficult prop to carry around. However, since I was going for the bot-fighting Hiro anyway, Megabot would be perfect. In case you don’t remember, Megabot is Hiro’s fighting robot made from three larger versions of microbots. It absolutely dominates and wins Hiro tons of money in bot fighting. You can catch scenes of it in the very beginning of the movie. If you haven’t watched Big Hero 6 yet, shame on you, and you should go watch it now.

I really wanted Megabot to be able to move like it did in the movie, with “floppy” arms and the ability to reassemble after falling apart. I had initially considered using elastic string connecting the places, but it would only allow for one of these features. Instead, I decided the best way was to use magnets and 3D printed parts. I did a quick search online to see what’s been done before and found Keith Lapinig‘s 3D printed Megabot! It was basically exactly what I wanted to do (with a few tweaks in configuration), so this was great proof that magnets would work!

megabot-crop-2    megabot-crop-1

Megabot has two faces: a smily derpy one and an angry game-face. In order to capture this effect, I decided (like Keith Lapinig) to make two heads that were interchangeable. It should be pretty easy, especially since all the pieces are completely modular. The other option would have been a double-sided head.

Like a true mechanical engineer, I CADded all of Megabot in SolidWorks first. I wasn’t sure exactly how many magnets I’d end up needing, so I left room for lots of magnets. The full CAD is shown below in the picture on the left. Some parts were made transparents in the picture on the right to show the magnet compartments.

megabot    megabot-transparent

In order to get the size of the parts just right, I made a couple test-prints. I printed the parts on the Zortrax printer we had in  the MakerWorks, but at that point, it was the only 3D printer we had reliably working, so I had to battle all the other people trying to print :P. In the mean time, I ordered some 0.5” diameter neodymium magnets on ebay and worked on robots.

At this point, work, robots, and life all got busy at the same time, and I wasn’t able to assemble everything until the day before flying out. I also had to paint most of the Lilo dress on the same day, so I fully utilized my multitasking skills.

I pressed the magnets into place for each of the parts and glued on the little magnet covers using medium-viscosity super glue. I then brushed a couple coats of acetone on all of the pieces to smooth out the surface, so the 3D printed surface layers weren’t as visible.

Megabot in a “disassembled” state

Once all the parts dried, I used several layers of a matte-finish black spray paint to coat all of the parts and let the parts dry overnight. The next day, I took out my acrylic paints and hand-painted the faces. Megabot was then ready to destroy.

The rest of the costume was pretty easy. I already had Hiro’s shirt and some tan men’s cargo shorts. The black Target-brand converse were surprisingly robust and comfortable, and yellow shoelaces were pretty easy to find as well. The wig, however, I spent a good 30 min attempting to style. Hanna, who cosplayed Gogo in our group, actually got a Gogo haircut and dye job. It looked amazing! I unfortunately do not look very good with short hair. Furthermore, I briefly discussed Hiro’s hairstyle with my hair dresser, and he insisted that while it looks good in animation, it’d be a terrible haircut to have in real life. Instead, Cynthia graciously let me have her short black wig from her Psycho-pass cosplay, which I then proceeded to furiously trim, cut, and style. For an amateur hair stylist? I think I did a pretty good job.

Hiro and Tadashi

I wore Hiro for two days of Dragon Con (for Micro Battles and Robot Battles) and spent it mostly wandering around with Tadashi (The Variable Constant/Jamison Go). We were pretty cute and had a fair amount of people stop to get pictures. On the second day, I even found another Hiro and Gogo!

Other Hiro and Gogo we found!

Couple things for future insight. After having to carry Megabot around in a crowded and busy place, I realized that using elastic strings to attach the pieces would have made a much better mobile prop, since it was hard to show off the features of the magnets anyway. Another option could have been stronger/more magnets. Another change I’d make is the face. I went with the two swappable heads because I thought it would make each configuration more accurate. However, while walking around a convention, it’s really difficult to get to switch the heads back and forth, so having a single double-sided head would have been much better. Next time!

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