I just realized that I'm a digital creature!

So I was driving my mom's car tonight, and I looked at the speedometer. I'm not used to it...it's one of those analog needle/dial speedometers, and I've gotten accustomed to my Prius's digital speedometer. It made me think of why we even represent data digitally...it reduces noise. Electrical, optical, acoustic, radio...any kind of signal picks up noise while it's being transmitted. But by representing data digitally, by having discreet thresholds from one value to the next, it makes it much easier to recreate the information in a signal without having to perfectly reproduce that exact signal (as long as the noise is below a certain level).

For (a very roundabout) example: You go to Wal-Mart to buy an HDMI cable for your sexy, new, flatscreen TV. You get there, and you discover that the cheapest one they sell is like $40. And some cables go for over $100!! You're like, "Why the hell is that so expensive??" You decide not to buy the cable then and decide to look online for alternatives. Online, you see cables that sell for less than $20. How do you know that the manufacturers of the cables at Wal-Mart are ripping you off?

Easy.

Because your new TV is digital.

Sure, an HDMI cable running to from your set-top box or Blu-Ray player might pick up all sorts of electrical interference along the way - from your wireless router, from other nearby cables, from fluorescent lights, from your sound system, etc. But by representing each bit of information being transmitted to your TV digitally, and by making sure the threshold between a logical 1 and 0 is greater than any noise the signal might pick up along the way, all the audio/video information sent from your set-top box can be perfectly recreated on your TV! You're not going to get "better picture quality" with fancier gold- or silver-plated connectors. Each bit of information is either going to be represented accurately or not.

So as I was driving, I was thinking, "If digital information is so good for handling noise, then why is the natural world so analog-y? Why aren't we all digitally-controlled creatures?"

And then it hit me...We are!

I remembered (from AP Biology in high school!) that neurons only fire action potentials when voltage across their cell membrane exceeds a certain threshold. That means there's a discreet potential that represents the boundary between a logical 1 (fire!) and 0 (don't fire!) in each of our neurons! Furthermore, fired action potentials are pretty much the same in magnitude from a particular neuron. Neurons that receive stimuli of greater magnitudes don't fire off action potentials in greater magnitudes, but they do fire off action potentials in greater frequencies! So basically, each of our neurons acts as both an analog-to-digital converter as well as a digital-to-analog converter (it's not exactly pulse-width-modulation (PWM), but it is SOME kind of modulation (see: http://en.wikipedia.org/wiki/Modulation#Pulse_modulation_methods))!.

So really, our bodies receive all this messy input stimuli from our environment (sight, hearing, taste, touch, smell), convert and process that data digitally, and then form outputs that are ultimately expressed in analog (example: movement of muscles).

I think that's pretty neat!

Sure, none of this is new. All of this is well-understood by those people who make artificial body parts that interface seamlessly with the human nervous system (pacemakers, robotic prostheses, artificial retinas, cochlear implants, etc.). Still, it was a delightful epiphany to make driving home earlier today.

At work, I'm programming a microcontroller on an Arduino board to control some other devices that will create a temperature gradient over a laser-microscope sample. For the record, this is my first Arduino project, and I'm a complete n00b at it. But basically, I'm just trying to get this device to be "smart" enough to make changes in output given certain inputs (from user-interface as well as environmental changes). It's all just receiving analog signals, converting them to digital, processing them, converting output signals from digital to analog and transmitting them, which is basically what my neurons do all day!

I'm always amazed with nature's designs. Evolution just provides you with a gazillion working solutions for so many practical problems, which is why it can be such a great source of inspiration for me, an engineer-in-training. As another (the final) example of this, I remember, again in AP Biology class, how amazed I was when I discovered that the simple concept of harnessing energy from a fluid flowing from high pressure to low pressure was implemented in each of our cells in the ATP synthase enzyme (see: http://www.youtube.com/watch?v=uOoHKCMAUMc). The concept of a dam/turbine seems so mechanical and human, but really, nature thought of it way before we did.

Goddammit, evolution. Why are you so cool?

Okay I'm done geeking out now. Good night!

PS: Sorry for oversimplifying the science in this post. I haven't really backed up any of my claims with...anything else. Most of this is all just from my very faulty memory, which works even less reliably when it's ~5 in the morning and I'm super sleepy. Corrections are welcome.

Making of the Rice Athenian Owl earrings

Hi, everyone. Just thought I'd show everyone how I made the Rice Athenian Owl (RAO) earrings. If you want to make your own, I'm not going to stop you, but why not just buy from me? =D

Find a picture of the Rice Athenian Owl. The Rice Athenian Owl logo has changed over time. The most recent one is the simplest. I used a more dated one that has more complex wings/feathers.

Edit in a vector-based illustration program like Adobe Illustrator. You can't just take the RAO logo, shrink it, and expect to laser-cut it well. Many points of the RAO logo need to be adjusted. A lot of edges need to be thickened up for laser-cutting. Also, the eyes need to be tweaked - in the RAO logo, the eyes are just floating crescents. To cut something out of plastic, you need the entire thing to be one continuous shape.

Finding the right material. I browsed online for material properties of various types of sheep plastic (PVC, styrene, nylon, acrylic, etc.). I knew I didn't want the earrings to be any thicker than 1/16" inch. I used 1/16" sheets of styrene, acrylic, and nylon for testing.

Testing. Because of the delicate nature of these earrings, they have for be cut pretty slow. Even if you turn up the speed on the laser-cutter, the sharp angles and intricate curves of the RAO shape force the laser spot to hang around any given area for a relatively long time. The heat buildup will cause surrounding material to melt. This was the case for acrylic. Styrene wasn't as bad, but it produced a lot of stringy-melted-plastic (like when you hot-glue something and there's that spider-silk-esque line of plastic). For me, nylon had the best performance. I had a hunch that nylon would perform well, since material spec sheets said it had the highest heat resistance.

Many failed test-cuttings...

This one had it's feet melted rather than cut...

Editing the picture again. When you're cutting, you'll find some parts of the earring will cut better than others. I had to go back and tweak the RAO image several times to minimize melting and breaking.

Cutting. Once you've got the right picture, material, and laser-cutting settings, it's time to cut the material!

Here are a bunch of freshly laser-cut pieces:

It just looks like a solid owl silhouette. That's because laser-cutters (probably) aren't made to make these tiny cuts on such delicate parts. A lot of the shapes that are supposed to be cut out have been melted and are still attached the main part. Even after tweaking the laser settings, this is the best I could do...

Cleaning. With an exacto knife. Very, very tedious. Other than testing, this is the most time-consuming step. Basically, you got to separate all the parts that the laser cutter was supposed to cut but melted instead. Obviously, the less detail the part has, the better the laser-cutter made the cut. For simple shapes like the holes around the eyes, basically you just need to poke those parts through. For the feet of the owl (that I'm shown cutting/cleaning below), that part is kind of a bitch. Fortunately, the nylon material has such great tensile strength properties and is rather flexible.

Still, you gotta be careful when cleaning. Some parts of the earrings are very thin. I think the thinnest point on mine is around a third of a millimeter.

After cleaning the main parts off, there's still a lot to do. Since the laser spot can cause local melting, you gotta scrape off those "globs" of material to make the shape as smooth as possible.

Aftermath of cleaning...

But after cleaning, you get a bunch of nice, pretty owls, ready to be painted!

Painting. This is the easy part. Go grab a can of your favorite color of spray paint and spray these babies down! I picked a bright metallic (kind of) silver because I really wanted them to stand out. I think they'd look especially good on a background of dark hair because of the contrast.

Assembly. Go to your favorite craft store (Hobby Lobby, Michaels, Joanns, Texas Art Supply, etc.) and find their jewelry department. Find some hooks and start assembling! If you don't already have one, get a set of jewelry pliers from the craft store - it'll make the assembly process much easier.

And there we go...a completed set of Rice Athenian Owl earrings!

So, if you're a Rice girl who's graduating or know someone who is, hope on over to: http://www.facebook.com/event.php?eid=143827832357034 to find out how you can buy a pair! As of now, I've only made 12 pairs, so hurry and order!

Hello, FORTRAN, my old friend

Here's the parody I performed with my friend, Kristie, at the ChBE Banquet. I first wrote this back when I was in 305. I appended it to the back of my Homework #3. Anyways, here are the lyrics. If anyone has a recording, please send to me, and I can post it here. KZ has requested a recording, which I might do with Kristie later if we have time.

Enjoy!

Hello FORTRAN, my old friend

I’ve come to code with you again.

Because whenever I use MATLAB,

I’m confined to a computer lab.

Thank goodness for the free, personal edition,

It frees me from,

SDL; it’s a prison

So I start writing line one

With your helpful IMPLICIT NONE.

So I don’t mean to make variables

Because of my careless typos.

But my code, like a faulty engine crashes,

Burns into ashes.

Looks like, it’s a night of Three-oh-five.

In restless dreams I code away,

Hunched over my laptop all day.

Finding roots using Bisection.

It’s too slow, so I use Newton-Raphson.

But my root, it diverges into Hell,

And so I yell:

Looks like, it’s a night of Three-oh-five

And next morning in class, I saw

Maybe 5 people, but no more

Hear the lecture, KZ might reach you

Read this code that he might teach you

But our eyelids, like heavy anvils fell,

We pulled all-nighters

Last night for Three-oh-five

And the students bowed and prayed

To their lab session TAs

We were already on week four.

Homework 2 was still on Charles’s floor.

And on OWLSPACE KZ has posted the next problem set,

He won’t relent.

Here comes, another week of Three-oh-five…