Mythbusters accidentally create a reaction-diffusion-like system

This short video clip shows that the Mythbusters appear to have accidentally and unknowingly created a kind of reaction diffusion system in their "Trailblazers" episode when they ignited a trail of gasoline. If you look closely behind Adam you'll see waves propagating in a manner reminiscent of various reaction diffusion and cellular automata systems. I think what's going on here is that the gasoline vapor and the moving ignition creates a two dimensional amorphous relaxation oscillator. Remember that it is the vapor of gasoline that is flammable, not the liquid. As the fuel evaporates into vapor it takes a few moments before it reaches an ignitable fuel to air mixture. When it does, a wave of flame propagates over the area thus eliminating the vapor which then slowly re-accumulates until it ignites again when it encounters an ignition wave from some other region. The exact position of the flame is highly sensitive to the environment and initial conditions thus the system turns into a set of chaotic cyclically flammable domains that move around in a fascinating manner. Apparently without knowing it, Jamie and Adam have stumbled upon a quite lovely piece of science. I've got to try to reproduce this!

Keyless Entry

I hate keys. I'm striving for a zero-key life. To that end, I've started on this little electronics project to automate the lock of my front door. There will be a discrete set of switches that look for a magical unlock sequence. I have an odd relationship with electronics. On the one hand I feel like I know the theory fairly well and I'm at home once the circuit is digital and connects to the computer. But in between those two is reality. The circuit seemed simple enough to just solder straight to the board. Bad idea. Meanwhile, I made totally rookie mistakes with the ground and managed to literally cross some wires. Also, I purchased a touch sensor IC (QT1103) because the data sheet said that it had an RS-232 out which is a protocol I know well from BBS modem dayz. Turns out there's a newer protcols (Dallas semiconductor's 1W) which is 100% incompatible with RS 232 yet mysteriously still uses the RS 232 moniker. So that caused me no end of confusion until I finally worked it out with the always helpful Wikipedia. Thanks to John sorting out my stupid mistakes and lending me a scope and protoboard, I've since started to make progress.

Back wall

Masonry is slow, tedious, heavy, dirty, at times back-breaking. All the pleasure is delayed -- a sense of accomplishment, an "I built that" satisfaction when you're done. I don't think I could have done such a slow and delayed-gratification task when I was young; what changes as we age that permits the patentice for such projects?

Some of the appeal of brickwork is the giant lego-ness of it. Or more to the point, old-school legos when there were only a few generic bricks -- before the marketing department at lego corrupted them into themed monstrosities with an over-reliance on custom single-use pieces. Brickwork tickles a nerdy engineering need for an elegant basis set from which solutions are cleanly constructed. But it lacks the playful impermanence of legos -- while I'm laying them I often think about the fact that these bricks will likely be the most long-lived thing I will make in my life. I wouldn't be surprised if 300 years from now my house has been torn down but the brickwork remains. Building things which are unobtrusive, durable, beautiful, and utilitarian is an almost guaranteed way to make sure they are maintained into the future.

Paper

Been working all week with Andy, Xi Chen, and Nam on a paper. Using the kinetics from Jongmin Kim's bi-stable switch paper, Nam produced a nice simulation of the amorphous ring oscillator. Happily, these images look much like my earlier, cruder, simulation but now have dimensions. Features are measured in mm and time in hours. I think that's pretty cool -- a molecular scale device producing features at the mm scale. Would be great if it actually works when we try it someday!



Also from this this paper, Andy, Xi Chen, and I came up with a hopefully plausible complementary transcriptional NAND gate. The idea is that all signals are encoded by the sense and anti-sense complements of an RNA sequence. For example, signal "A" is high when some specific RNA sequence is high and it is low when the anti-sense of that sequence is high. The hypothetical gate is made from two complementary promoters on opposite sides of an double stranded DNA. On the left side, two molecular-beacon-like devices sequester half of a promoter that activates only when both inputs are high. On the right side, a single hairpin is folded such that a promoter is normally active but is deactivated when A and B invade (thanks Xi Chen). To work, the kinetics will have to be very delicately balanced so maybe it won't work well but at least it's a conceptual step in the right direction; we've been talking about a CMOS analog for years now and this is the first time we've made any conceptual progress.

Finished door panel prototype

Actually I spent most of the day working on a paper with Andy but there's no cool picture for that. Afterwards I finished the door panel prototype. I think they look pretty good but they were a real pain in the ass. I'd like to do it all over the house but I think I'll wait until I have access to a large mill.

Old media to new media conversion rate? Negligible

I was curious as to what the conversion rate might be from old media such as Science Magazine to new media like this blog so I tracked the hits of this blog during the publication of the Science article about me last week. The answer? Anemic. On the day of the release, only 90 visits to this blog and most of those came from HackerNews because my friend Jim posted it there. Granted, that's a lot more than the background of near zero, but compared to times when my website Mine-Control has been mentioned in obscure blogs, it's nothing. For example, an obscure Spanish art/video site once linked to Mine-Contol and I ended up with a $1000 monthly bill on bandwidth after tens of thousands of hits. A single tag on a social bookmarking site like digg usually generates thousands of hits. So, despite the fact that lots of people read Science, the conversion rate is apparently low. Of course, this is a single biased sample and it might just be that nobody cared enough about that article, but I suspect that it wasn't that much different in interest than any of the much higher converting blog entries I've been on the receiving end of before. So, thinking of advertising in old media and hoping for a lot of resulting web hits? -- maybe not a great idea.

More back seat wall progess

Christmas day progress on the back wall. I built a temporary mold with bricks and leveled out the top surface in preparation for the seat course.