Gelatin brain mold with arduino synapses


A while ago, I had a spectacularly bad accident on my bike. There was a dog, a leash and a human. The leash acted kind of like a finish line ribbon, but without the breakaway segment they use in the proper races and marathons. I landed on my (helmeted) head. Hard. A few hours later I came to in the ER of the local hospital blabbering to my wife, asking the same questions over and over (and over). They ‘offered’ to let me stay there a while, so I took them up on the offer and spent the night.

For a long time, I have consistently worn a helmet on every bike ride. It always puzzles me to see adults and kids riding with out proper head protection. I also often see teens with skateboard helmets riding with the straps undone, as if having the protective gear perched on their head is enough to keep it there. Why not clip the straps? If I hadn’t had a helmet on and properly secured to my noggin, I’d still be on the hospital feeding program, if I even survived my brief flight.

As I was floating in the ER I got a vision: A brain with little toy objects suspended in it like ideas in a mind. Around the objects are blinking lights acting as synapses. As I recuperated in the days after my misadventure, the image continued to return for further refinement. One of the first things I did on return from the hospital was to order a gelatin mold in the shape of a brain. It arrived very quickly, much sooner than I could have hoped.
Doctors’ visits occupied most of my next few weeks, with long hours of not much to do. Playing with the idea of the brain mold was a good way of keeping from getting too bored. “Synapses. It will need synapses. Lights will flash in the brain, kind of like the electrical impulses that carry our thoughts around.” LEDs would work fine for this, I figured. These LEDs wouldn’t just go on and stay on like a traditional circuit, they would need to be controlled to blink. I started to look into Arduino. I’ve got a few books around on how to program and build for Arduino: Getting Started with Arduino and Making Things Talk both had good ideas, but neither had exactly what I was looking for. I did some searches for learning Arduino and came up with this great set of tutorials on Arduino basics from Lady Ada.

In following the tutorials, I found that a lot of the information was familiar from earlier forays into Arduino. The code samples were helpful. As I went through, I was trying to picture using these tutorials in the classroom with students and found them to be segmented too long for the time frame of a class period.

In Lesson Three, which introduces the breadboard and the possibility of multiple LEDs being controlled by the Arduino, I got some crucial lines of code and later reached a point where my desire for the code separated from the direction of the tutorial. I had added extra LEDs to my array on the breadboard, and had explored plugging them in to the Arduino from pin 0 on up to pin 13. I found them to work predictably in each of the pins, with the added benefit of seeing the LEDs in pins 0 and 1 flash as the program loads onto the chip. Here is the code that I settled on. By Wednesday (accident +8) I had the basics of the program written and tested on the breadboard, demonstrating that it could work. Here is the code as it ended up for this project.

Having the LEDs on the breadboard works OK for testing the idea, but once it is proven, the next step is to make it more reliable and durable. To do this, I soldered braided wires onto each of the LEDs. I used some stranded CAT-5 wire that I keep in my wires and conductors storage bin. Each pair of wires to the LEDs is about 10 inches long, giving enough distance to connect to the board. All of the negative leads are covered with heat shrink over the soldered joint, and then both leads are covered with heat shrink tubing to keep the connections separate. The outer tubing was stiffer than the inner, so I heated them up and bent them at 90 degrees for a flatter installation later. I wired a 1k ohm resistor in series with the common ground for the LEDs to limit the current.

The gelatin part of the mission was accomplished on the way back from yet another appointment. I got lots of pretty colors and tasty flavors. In purchasing the gelatin, I just went with an off the shelf option, but realized later that you really should mix up a special recipe. What I should have done was dope it with additional gelatin to make the molded goo much firmer. Another mistake I made on this first gelatin mold project was not putting a release agent on the mold before pouring. Getting the mold to separate from its’ contents was more challenging than in it should have. Ultimately, I used a warm towel over the mold to melt the outer edge. This had the effect of softening the surface. Non-stick cooking spray would have helped.

One of the original concepts in the vision was to have things inside the brain. The things would be what the person is thinking of. I knew I wanted animals, and was curious to see what else was available. On the way home one day, I stopped in to the craft store to gathered my critters. I found these cool tubes of plastic animals. They’re similar to the ones my daughter grew out of and we sent to her cousins in Malawi. These new ones, however had the added benefit of being more than just animals. I had to hold myself back from scooping up all the whales, cars and trucks and lots more. There wouldn’t be enough room for all those thoughts. I settled on dinosaurs, safari animals and…space with astronauts, space stations and rockets. It would have been cooler if it had Laika, the first AstroDog, but it did have a monkey in a space suit.

At this point, all the pieces of the brain puzzle were in place. Brain mold-Check…Lots of gelatin-Check…Ideas to float in the brain-Check…Programmed synapses-Check

On the morning of the unveiling, I had a few loose ends to tie up. The brain needed to be poured, and the synapses needed to be put in place on the base. I had added a few more LEDs, and it would be nice to program those as well.

The gelatin needed to be set with the critters embedded in it. This would take at least three pours, as I wanted to have things at all levels of the brain. In mixing it up, I used a combination of ice to chill it with and putting the mold in the freezer. This helped speed up the process. The plastic animals sank to the bottom, but could be jammed into the already set layer below.

When we arrived at my parents’ house before dinner, I set to putting the LEDs into a piece of the cardboard box that the mold shipped in. Using my Warranty Voider, I poked holes in the cardboard and inserted the LEDs. A bit of aluminum foil helped create a reflective surface around them. The best thing for a stand turned out to be a wooden clementine box from the basement. Wrapping the assembly in plastic cling wrap helped to keep the electronics away from the wet gelatin. Switching the jumper to external power on the arduino meant that it could be plugged in to the wall instead of powered by USB.

So next time you get a vision of little objects floating around a gelatinous brain, maybe you can break out your Arduino Duemilanove and make up some synapses to better illustrate your vision.

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