As we built our Redd Blooey Greene character, it occurred to me that I could “easily” make a servo powered control system for things like the eyes, brows, and eyelids for these characters. It turns out, I wasn’t right or wrong. Yes, I can indeed make servo control systems for these guys that borderlines on easy, (and relatively cheap), but it also has taken far more work than I originally anticipated. Not much though.

      As we got to working on this guy, my imagination started running wild with possibilities, and I began designing a fully articulated face setup in Maya with the idea that each puppet is different and would thus need its own set of controls and functionality. I wanted to create a system that was expandable, using one control setup to power any number of different face setups. For instance, Redd is only going to have eyebrows that move, but other puppets may need eye lids, or even fully articulating eyes. So, I began going down a dark path of utilizing Arduino Uno boards and a package of cheap servos to figure out how to make all of this possible.

      It started with simple prototypes. First designed in CG, where I can easily move things around and test them without having to build them. Then it moved in to prototyping with hardware. This step required some creative ingenuity on my part. A lot of the things I wanted to build don’t really exist for my purposes, so I started finding things around the house (and a few things at hobby stores) to start cobbling together a few working models. I used a corrugated plastic sheet for my structural building materials, ping pong balls for eyes, hobby wire for some of the mechanisms, and spray bottle caps for raw materials for making tiny gimbals.

      I had to find two bottle caps of varying sizes in order to make my gimbal system. All of this has to be super lightweight, so a thin plastic was ideal for this. I sliced rings out of the bottle caps and then using some hobby wire, I made gimbals out of them with a larger and smaller ring nestled inside each other. This worked perfectly, and after some fiddling, I had a working eye articulation method that could be built upon using servos to actually mechanicalize.

      Now, the thing about this is, since Redd is the first character being built, and his eyes don’t move, I needed to focus my attention on the eyebrow system. For this, I prototyped with the same corrugated plastic sheet, some hot glue and some more hobby wire to build a functional puppet eyebrow system. I even tested this setup with a servo, and it all worked as expected.

      Now, I had to try and build a production model. While it’s still technically a prototype, it’s one that will ultimately make it into Redd’s head. I still used the corrugated plastic sheets for building the frame. It’s super lightweight and relatively sturdy stuff that takes the hot glue, as well as some screws and wires very nicely. It’s not sturdy enough to handle you sitting on it, but it’ll hold up for what it needs to do.

      Next it got technical.

      I used Libre PCB software to help design a circuit board that would plug into an existing Arduino Uno Board* and make a shield that would service all the servos I would need to run varying puppet types on a simple 2 joystick controller that could then plug into a separate puppet brain circuit that would run the servo mechanisms in any given puppet. I designed it to work with a simple RJ-45 network cable that would go from the controller to the head and makes it hot-swappable for any puppet.

      Now, I could have gone with USB-C, or even Bluetooth for this connector, but given that this was my first project, I wanted to make it relatively bullet proof, and worry about higher tech later on. Part of the reason that I didn’t go with USB-C was that the components are so small they’re incredibly difficult to solder by hand. RJ-45 cable was bad enough, I can’t imagine trying to go smaller.

      I stared using some pre-drilled project PCB boards (I know – redundant), but they quickly became problematic, and I asked myself the question, “How hard is it to actually print your own circuit boards?”

      It turns out, not that hard. Although, the trial and error took me several rounds to get working. Going back to Libre PCB (which is a free software for designing circuit boards) I laid out all the connections that I knew I needed and the started trying to print up the boards.

      Basically, you invert your design, print it from a laser printer in black and white on matte photo paper and then use an iron to transfer the ink onto a copper plated silicone board. You can use a sharpie marker to fill in places that didn’t quite transfer properly (I ended up tracing everything for evenness) and then drop the board into Ferric Chloride etching solution to eat off the part of the board that wasn’t covered in ink. I’d like to say it worked perfectly, but that would be a lie. It actually took me several tries to get a viable board that would pass my ohm-meter test and work as a controller.

      Below are my various attempts at getting to a final mechanism. I’d like to say it’s over and done with, but for all my efforts, I’m getting a serious twitch out of the left eyebrow. I have to weed out what’s causing that, but otherwise this crazy system is working!

      You can see the current state of the character, and then many of my attempts to get to the final prototype. It’s been a bit of work, but I think it’s going to be worth it in the end. I did find out that I can easily get professional companies to print up my circuit boards, including all the soldering and component placement for about 2 bucks. Once I get all of this working, I’ll design a smaller board that doesn’t require the Arduino and I’ll have them printed up professionally. But until then, here’s my proof of concept.

      • Arduino is a company that sells pre-made circuits for doing prototype building. You can plug servos, lights, Bluetooth or any other kind of sensor into it, program some C++ into it and get your projects off the ground quickly and easily.

      Hi, I’m Adam Benson

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