Opening Doors

By Ben Nitkin on

Second post! That's a thing, right? Good.

Last time, I got as far as reading out bits from the card. I noticed a few things about the output bits:

  • The first half of the code was always the same.
  • The code was around 35 bits long.

With enough cards, I could have reverse-engineered the card code, but Cyborg Mode is easier. A few quick searches turned up a site explaining the HID format. In essence, the card has two pieces of data stored on it: a 12 bit facility code (same of all Lafayette cards), and a 20-bit card code (different on each). A quick aside: 220=1,048,576, so Lafayette's 2,500 students use only a smidge of the possible combinations.

Reading Secrets

By Ben Nitkin on

See that picture? Good. The college uses readers just like those all across campus for access control. They're on the front of all of the academic buildings, all the dorms - just about everywhere uses these phobs.

A few days ago, I bought one of them. (It's wild what you can buy on EBay. Really wild.) The reader arrived on Monday, and sat around for a while. Midway through the week, I decided to have at it.

Serenity

By Ben Nitkin on

Serenity. Recognize it? Good.
I sketched this in the week I had off from school. Looks pretty cool. It's going on my door.

Leonardo!

By Ben Nitkin on

I'm living in an LLC. It's a new program that offers Lafayette students a chance to learn about a topic in themed housing. My house, Monroe@, is technology themed, which means I can do all sorts of fun things in the name of learning!

One of our projects for the year will be automating the house's door. We all carry HID RFID fobs for access to campus buildings, and want to enable the door to respond to those phobs. All we need is a reader to read our cards, a servo to turn the deadbolt back for a second, and some brains. I have servos already, so I went to the internet and bought an Arduino Leonardo for brains, and a HID brand reader for reading.

Guess what came yesturday? The arduino! I know that the things are bashed for being overused by hobbists, but they're so much easier to use than microcontrollers in C.

I wanted to play with it, but didn't have any parts. There are a pile of leftover LED's at the house, but nothing else. No buttons, no fancy inputs, no resistors.

Vigenere

By Ben Nitkin on

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What would you do if you saw this message in your inbox?

Space Shuttle Liftoff

By Ben Nitkin on

The Space Shuttle Atlantis, as it lifts off from Cape Canaveral. (Still a work in progress. I like how the gantry loses detail near the shuttle's base, but want to add some smoke and fire.)

I had to crop the png image, cause the site doesn't have enough RAM to generate thumbnails of the original sketch. No detail was lost in the process. Awesome alignment suffered, though.

Hubble Space Telescope

By Ben Nitkin on

This is the Hubble Space telescope, captured as the third shuttle mission to repair the telescope departed.

The sketch is hanging out on my door, the first of many.

The site can't make thumbnails of large images. Evidently scaling a 12MP image takes about 30Mb of RAM, and the site only has 64Mb total. Alas. (The full size pictures are cooler, but take what you can get.)

Yin-yang

By Ben Nitkin on

I'm still looking for a decent logo. Eventually, I hope to use a stylized blue brick. That name has a story behind it, and it evokes tinkering, so I'm keeping it. (This site was Rock Lizard for a spell, cause that's what Evan and I wrote.) One idea I had before invoking the new name way a yin-yang type thing. (As the favicon illustrates, I like little mathematical graphics.)

Alpha Logic Gate Simulation

By Ben Nitkin on

In ECE211 (that's Digital Circuits I, for those of you who don't go to Lafayette), we've been working with digital circuits. Surprising, right?

I was frustrated that I needed to draw out these complicated circuits by hand, and that the paper never gave me any helpful feedback. So I decided to write a logic gate simulator, using my favorite language for graphics, Processing.

Critical Repairs

By Ben Nitkin on

A while ago, I found some electrical solder. I was excited. So much so that I had to hammer out something random, using parts I had on hand. The result was an adaptor that would connect my computer's 3.5mm sound output to a stereo's twin RCA inputs.

As I've said before, it worked perfectly. With one qualifier. It just broke. The 3.5mm jack I used had fairly flimsy legs, and they gave up after a few weeks of being bent back and forth.

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