Costume electronics, I've put it off long enough

Arduino Uno on the left and Raspberry Pi on the right

I've been putting off adding electronics to my costumes, even though at least one of them (Darth Malgus) would have benefited. However, I'm now at the point with the Ithorian build when I've got to add some motion control. And, there are a lot of features I'd like to add that will require additional electronics.

But here's the thing. A big part of my career has been building electronics, and I've been pretty burned out on it. It's hard to have my hobby so closely match my work. Although currently my work has been mainly software engineering, I come from the early computer revolution: designing and assembling digital circuitry, embedding microcontrollers and firmware into equipment, and working in the robotics industry. My graduate work was in Electrical and Computer Engineering since UCSB didn't have a software track (remember, I'm an elder geek). Ever since I was a child I did a lot of hobbyist electronics (analog), and as an adult I built a lot of home robots (digital). But after many years, I burned out on it all. I occasionally solder a few wires or check continuity on some circuitry, but I never dive deep into the latest SBC or other electronic project.

Now though, I need to add some servo motors to the Ithorian costume in order to move the eyes and the eyelids. I'd like to flash some lights on Malgus' control gauntlets and chest plate. So it's finally time to face the current maker zeitgeist and explore what's available for the hobbyist.

The main building blocks are: power, sensors, actuators, wiring, and logic. Of them all, the logic is the central component that will have a significant impact on all the other components. So I'll start there.

Sitting around my office are the two most popular control cards currently available for the hobbyist maker. The first is from the Arduino family of controller cards, the Arduino Uno. Arduino is open source and has been popular for many years now. The system seems easy to set up and program, is small enough to be embedded in any costume project, and has a lot of community support as well as multiple manufacturers of add-ons and accessories.

Also, I have a Raspberry Pi. The Pi is a relatively recent development, but it already has a huge support base and user community. There are a lot of additional peripherals and components that can be purchased from third party suppliers. It's a little more difficult to set up, but it is very powerful.

Which one to choose? I don't know, so I'm going to learn and work with both of them initially. At some point, i'll make a decision on which platform to keep for my particular needs, but I may find that I need different systems for different applications. I'll post my progress with both, as well as the bits and doo-dads I need to add to accomplish a particular task.

First up, blink and eye movement using servo controls!




Vacuum former: update 5, finished! (more or less)

Completed (nearly) vacuum former!

Here's the (nearly) finished vacuum former! Although there are a couple of fixes & improvements to be made, it's complete enough to start pulling parts.

Spacers added to the frame near the handles.

Spacers provide a tighter fit to the vertical guides.

I added some guides to the frame in order to more accurately guide the frame between the heater box and the vacuum platen. Now the frame lands perfectly around the platen every time.

The quick latch made from angle bracket bolted to the frame, an eye bolt, and a wing nut

I also added a latch to the frame so that I can quickly load it with styrene and lock it down with an air tight seal. The position of the eye bolt & wing nut are just outside the spacing of the heater box so I don't get any interference in either the heater or vacuum positions. And, the 12" x 16" size of the frame let's me cut up a variety of standard stock sizes without any waste: 12" x 48", 2' x 4', or 4' x 8'.

Magnets affixed with J-B Weld (corner) and 5 minute epoxy (front & side)

The final addition to the frame are the magnetic holds. I epoxied 12 neodymium magnets around the frame and another 12 embedded into the heater box. This holds the frame against the box in the upper position while the plastic heats. When it's ready, I pull the frame away from the magnets and slide it down over the platen where the vacuum pulls the pliable plastic around the pattern forms.

This part of the former gave me the most trouble. First, I ended up needing more magnets than I anticipated. And handling the epoxy required developing a reliable procedure. I started with the J-B Weld, assuming that my prior success with the wooden to metal offsets would mean quick and easy success with magnets. Nope! It's messy and the fine control I needed to position the magnets in the frame required longer than the very short setup time. And later, one of the magnets pulled away from the frame.

So, I went back to my more familiar 5 minute epoxy, and it still took awhile to figure out how to effectively position the magnets, and find tools that weren't subject to magnetic forces! I also ended up drilling mounting holes in the heat box, partially to give better epoxy mounting, but to also bring the magnets from the heater box closer to the magnets from the frame, without the aluminum box frame getting in the way. I finally got everything mounted and working, but it's ugly and I still have one magnet that needs to be reinstalled.

At this point, I had completed enough to try vacuum forming. I had tested the heater and vacuum wiring a bunch of times & it always worked. So, I put my 1st piece of plastic in, moved the frame up to the magnetic hold position against the heater box, placed the sample pattern forms, turned on the heater and watched the plastic heat & droop. Once it looked ready, I quickly dropped it over the forms and platen and then switched from the heater to the vacuum.

And nothing happened.

The orange switch burned out and needed to be replaced

I tried the switch several times and the vacuum never came on. So I tossed out that piece of plastic and began troubleshooting the problem. After ringing out the fuse and wiring, I finally found out that the switch had fried! Luckily, I was able to find another 3 position, high current switch at a local Radio Shack, and was able to replace it the same day. Then I did another test.

A couple of things in my shop that I used as buck forms

I grabbed a spray can lid and an abalone shell that I happened to have in my shop. They were sturdy enough and heat resistant enough to be good forms, and the vertical lines of the lid would be a good test of a tall, straight part. Also, the lid has raised lettering, and I can see how well the form would pick up detail.

The 0.03 styrene successfully vacuum formed!

And it worked! The plastic heated and became pliable after a minute or two. I saw the characteristic droop, and then dropped the plastic down onto the forms. I quickly threw the switch from the heating to the vacuum position, and the plastic was pushed down to form over the patterns. There was some webbing (those vertical fin-like pieces that branch off from the lid with one running over to the shell), and the shell had some overhang which locked the shell into the plastic. I was able to work the shell out, and the lid popped out pretty easily. I cut out the two pieces and cut off some of the webbing although I didn't meticulously clean up the pieces. Still, they came out very nicely for my first vacuum forming.

Four standoff feet added to the bottom of the vacuum box

Two more components were added to the build before I stopped for the day. First, I added stand off feet to the bottom of the vacuum box. I used the 4 feet that came with the toaster oven I had dismantled. The feet were necessary to lift the vacuum box off of the table. When the vacuum former is standing upright and without the feet, the lower box forms a seal with the table, and the out flow of air from the shop van when it's turned on causes the box to lift up off of the table like a hovercraft. Until I added the feet, I had to place spare boards under the corners of the box to give the airflow an exit path.

Adding a protective face to the heater box

Finally, I placed a protective face onto the heater box in order to shield the operator from the 110 V going to the heater elements. I only did the one face, but intend to place an aluminum facade over the additional 3 sides later.

And that's it for now. The following open items aren't critical, so I'm going to set this project aside so that I can get come other projects done, and so that I can use the vacuum former to make some props!

Remaining to do:

  • Replace the pilot light
  • Remount a magnet that come loose
  • Add 3 more sides to the outer heater box


Vacuum former: update 4

Progress at the end of the day

Today I mounted the platen to the vacuum chamber and finished the wiring.

The platen screwed down to the walls of the vacuum chamber; also shown is the frame bracket for holding the plastic

To attach the platen to the vacuum chamber, I first thought about using J-B Weld. However, I like being able to disassemble a piece of equipment for repairs, so I decided to screw the aluminum plate down to the wooden support. I put a screw in every 4 inches or so and it seems to be holding securely. I'll see whether it's air tight enough when I try to vacuum form something.

I finally got to the wiring today. Everything went together well once I found my soldering setup. I only needed to solder a couple of leads to the fuse holder. Everything else is attached with high temperature twist nuts. 

I wired in the shop vac first, and that worked great. Then I wired the heating elements and discovered that the pilot lamp doesn't work (I probably damaged it when removing it from the toaster oven), and that wiring all the heating elements in series doesn't generate enough heat.

I rewired so that two heating elements each are wired in series. Then the two pairs of heating elements are wired in parallel to the power switch. That worked much better so that the heating elements warm up very quickly.

With the wiring complete, I have the following items left to do:

  • Put a protective set of walls around the oven box. Those are exposed live wires when the power is applied
  • Add a latch to the frame bracket
  • add spacers to the frame bracket right next to the handle in order to remove some of the slop when moving the frame bracket from the oven to the vacuum
  • Add magnetic holds between the oven box and the frame bracket
  • Replace the pilot light