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Showing posts from 2011

Fun Google maps satellite image find

I found this image on Google maps satellite images the other day. It's a E-3 Sentry taking off from Tinker AFB near Oklahoma City. At first I thought it was a KC-135 (and that's what it went out on Twitter as) but then I noticed the rotodome on top. It's neat because you can see the sequence of images as captured by the satellite. In the first "frame", it's just starting to pull away from the ground, and by the last frame it's well off the surface and past the end of the runway. You can also see the procession of the rotodome- the band of gray in the disk shows the rotation.

What is the propagation speed of a yawn?

On the bus the other day, as I was rolling past waiting commuters on Marquette Ave in downtown Minneapolis, I saw a yawn traveling along through the crowd. Or at least, that was the appearance- it may have just been that people were randomly yawning as I passed. Regardless, that got me thinking: what is the propagation speed of a yawn through a given crowd? We should be able to express that as an equation, if we choose our parameters wisely. First, let's define "speed", for the purposes of this exercise, as the time required for a yawn to travel a given distance through a crowd in any direction. The reason for that wording will become clear later. So, that brings us to the equation: V = d * q * (m / r) * f(C) where d is the average delay between when a person sees a yawn start and starts yawning themselves m is some distance factor (it can be observed that someone closer is more likely to inspire a yawn than someone farther away- m will have to be determine experi

Why Dunbar's number matters

So, I cast a fairly wide net in terms of things I passively track for potential food-for-thought. Blogs and tweeps, books, articles, etc- I try not to limit myself too much because I can skim pretty quickly across a fairly vast swath of content, even if it IS just a drop in the bucket. This morning, the following tweet came through, from Tim Hurson : To ourselves we are a complex of thoughts and feelings. To others we're just a bunch of behaviors. Really not engineering related, of course, but it meshed well with something else I saw come through my twitter stream- a post about Dunbar's number, which is the supposedly optimal group size of human culture: the number of people that you can conceivably know about and care about. That group of about 150 individuals is your monkeysphere , and people outside of it are, to some extent, not really people in your mind. I think there's a little more to that tweet than the 140 character limit allows. See, to people who consider y

UptownMaker goes to the Faire

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This past weekend I attended Maker Faire in San Mateo. It was an absolute gas (does anybody use that phrase anymore?)! I'm going to do a few quick posts highlighting my favorite sights- all my pictures and videos are on my Picasa site . I'll start out with my favorite first: Miss Haley Who, swamp kirin wrangler. This lovely fellow is a mechanical swamp kirin. He stands about nine feet tall and though he looks ferocious he's really quite gentle. Haley Who, aka halo seabat, built this majestic creature as a gift for her little brother, Seth. It seems Seth was a bit heartbroken after their father explained that the few remaining wild swamp kirins in the east were best left unmolested in their natural habitats, and halo took pity on her brother, building him this mechanical version. The pair of them wandered about the grounds, charming the pants off of just about everybody they met. Haley's disarming smile, the kirin's gentle gait and their tender interplay sof

USB CDC toy

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This was originally going to be my calling card for Maker Faire. It's a very simple implementation of Osamu Tamura's AVR-CDC project , realized without a board. I had planned to make it a small device that can be plugged into a USB port and observed on a terminal spitting out information about me. The Great Global Hackerspace Challenge project took a lot out of me, though, so I didn't get it done in time. The blobby on the left is an I/O module- three input switches, three output LEDs, and a reset switch and power LED. It plugs onto the header that is currently being used for programming. The circuitry is pretty simple: 100nF bypass capacitor, the 5V in from the USB port goes to the positive supply pin through a 1N4001, and the USB D+/D- are connected to a couple of the I/O pins. Some words about that 1N4001: it was chosen specifically for its high forward voltage. See, the USB input wants a 3.6V input or so, and the AVR doesn't want to run at the 16+MHz needed for t

Inductive power

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About two years ago I decided I was going to figure out a cheesy inductive power coupling circuit. I sat down one Sunday, started plugging some stuff together and this is what I ended up with: This is the circuit I brought with me to the "bring-a-hack" dinner at Harry's Hofbrau that Jeri Ellsworth organized on Sunday night. You can see that the LED in the jar is lit- the jar is really just a gimmick and the little parasite works better outside the jar. The circuit is very simple: the IC in the middle is a 12F683 that I programmed up to be a square wave generator (someday I'll blog that project, but for now, I'll just say that the oscillator frequency is jumper selectable and it can be set to either update constantly when powered or set and forget the output frequency and duty cycle) running at 50% duty cycle and (approximately) 71kHz. The square on the right is a bit of ~28ga magnet wire wrapped a few times around four screws. Power is delivered to it by a tr

Do you see nouns or verbs?

A friend of mine recently posted to Twitter a picture of an object that his 19-month-old identified as "K". That got me to thinking- clearly, she knows what a "K" is, but it doesn't exist in the "privileged class" of objects that we arbitrarily refer to as "letters". Hence, she was able to spot a "K" someplace an adult would never even look for one. At her age, she still sees nouns everywhere she looks. That doorstop LOOKS like a "K" so she identified it as such. As adults, we live in a world of verbs. We look at that object and see a doorstop- which is to say, we see what it DOES rather than what it IS . There's an important distinction there, for makers and artists especially. We tend to be so wrapped up in the verb form of the world that we forget the noun. My personal experience with this has also been that even when I succeed in considering an alternative solution to a problem, I STILL verb-ify my solution,

Atmel's XMEGA- What's the deal with 'A' and 'D' families?

Too busy to blog lately. I need to change that. Today I'll be doing lots of gateware builds on a project so I'll have some free-time. I attended a seminar last week about the picoPower capabilities of Atmel's UC3, Atmega and Xmega processors, and it got me hankering to start working with the Xmegas. It did not, however, give me a good answer to a fundamental question: what the heck is the difference between the 'A' and 'D' family of Xmega parts? Some Google searches failed to turn up a result, so being a good little creator of value, I thought I'd do the research and make a post about it. For more information about the Xmega in general, EMSL have a good starter article . In short, they are high-ish pin count, 3.3V microcontrollers that add some really nice features to those available in the Atmega parts. They come in two flavors- 'A' and 'D', with 44, 64 and 100 pin count devices and QFN, BGA, and QFP package options. They also have

Engineering definition: elegant

Elegant (adj.): “I’m being an unnecessarily clever d!ck about this, and that’s going to open up a lorry-sized hole in my design that I won’t see because I’m being too smug about how clever this solution is. Oh, and it’ll be harder to fix, understand, build, troubleshoot, and use, but I saved $.000001 on each unit by committing untold future resources to solving the problems I don’t know I just made. It also took far longer to design than it would have had I done it in a more conventional manner, but that’s okay, because design time is free and per-unit cost is king.” KISS is the alternative to "elegant", and frequently results in designs which are MORE elegant than trying to be clever produces.

The Power of the First Time

No, not that first time (well, not exclusively). Think about the first time you did something that scared the hell out of you.  For me, the best example is the first time I set out to ride a rollercoaster and actually enjoy it.  Before, the tiny number of times I'd been on coasters were all profanity-laced panic-attack-like attempts to assert my masculinity.  This time, however, I decided to seize my fear and enjoy the ride.  It worked- that summer, and the two years thereafter, I bought a season pass to the local theme park and racked up literally hundreds of out-and-back trips, and I made a couple of special trips to other theme parks to hit THEIR coasters, too.  Something that had been previously unimaginable became a source of tremendous enjoyment to me. What about the first time you used a tool you'd never used before?  I was terrified of the vertical milling machine until the first project I used it for; now I can't imagine NOT having access to it. Or the first

A Maker's Notebook

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I've long suffered from notebook envy.  Not envy of any particular notebook; I just always wished I could be one of those people that carries a notebook around and jots down notes on everything - stuff they want to look up, buy, make, write about, talk about, whatever. I never HAVE been one of those people, for a number of reasons.  I'm scatterbrained, so even if I did have a pen and notebook, they'd have to be pocket-sized so I can not have to carry them around, or I'll lose them.  I hate writing (I actually have a mild learning disability which affects my ability articulate ideas with a pen and paper), so I'm not likely to be writing draft blog posts or a novel in my notebook.  I can't draw for crap, either, and I don't have much interest in developing that skill.  I also never found a notebook I really liked- they're too big, or too rigid, or the paper is too thin, or they are lined/gridded wrong.  I'm very Goldilocks on this. I like the Maker