Timelapse-o-Tron™ 9000, part 1

posted in Electronics by Cargo Cult on Wednesday June 13 2012

Computers are way too fancy these days, with their gigabytes of memory, gigahertz of multiple processing cores, hyper-parallel GPUs and terabytes of storage. Sometimes we nerds yearn for a simpler age, when processors were real processors and programmers were real programmers.

So last year, I got into microcontrollers, via the hipster-compliant, super-straightforward Arduino platform. 16MHz! 32KiB program memory! A whopping 2KiB of SRAM! All in a neat and tidy little circuit board with oodles of connectivity:


But what to do with such a thing? I rapidly got it to blink morse code on a tiny on-board LED upon receiving terminal data, but that seemed too simple. I needed something altogether fancier; something that tied in with my frankly excessive number of cameras; a project that absolutely nobody had ever thought of before. So, an Arduino Intervalometer was it - seemingly a nice and straightforward introduction to programming something less powerful than my first computer, back in 1988.

Some research online revealed pinouts for EOS external trigger sockets - the 'communications protocol' turning out simply to involve short-circuiting things to the camera's ground. Flashy new diagrams here for maximum information-dump-ness:

2.5mm connector, causes short-circuits on the way in and out - nice.
Low-end Canon (350D, 400D, 450D etc.) external trigger. Short 'focus' to 'ground' to focus, 'shutter' to 'ground' to release shutter.
No short-circuits, completely non-standard. Yay!
High-end Canon (40D, 7D, 5D etc.) external trigger. Same as before. Best to test wires inside the cable by shorting them while it's connected to the camera - otherwise it's impossible to identify the gits.

My Canon PowerShot G10 had the 2.5mm connector, the same as my converted-to-infrared EOS 350D. But the 7D? A distinctly non-standard Canon effort. How to obtain a connector without buying an expensive Canon remote trigger? Turned out to be simple - by buying a cheap trigger from Amazon. Easy! Chop cable and connector off, tease out internal wires, identify them and that's it.

I decided on using 3.5mm audio cables as extensions, using a 3.5mm-to-2.5mm adaptor for the lower-end cameras and soldering a 3.5mm headphone-style jack onto the end of the higher-end cable when it eventually arrived. A 3.5mm headphone socket would act as the connector into my circuitry.

After breadboarding-up a brainless version with a couple of microswitches, I started looking into interfacing with the Arduino. One problem being that the protocol is so utterly dumb that it ignores such niceties as 'digital levels' and 'known voltages'. I needed something to isolate the camera with its mysterious voltages and currents. Relays? Too chunky, and moving parts are noisy and prone to wear. Only one thing for it: opto-isolators.

While trying to find where to buy the blighters (Radio Shack had a fine line in antiquated relays suitable for Edison-style currents), I checked SparkFun online - where they not only had some opto-isolators perfect for interfacing with an Arduino, but someone in the comments had already used the things to control a camera.

So, let's breadboard it up:

Fritzing's PNG output is terrible; this is a screenshot.
The connector may or may not be round the right way. Please take with a pinch of salt - reverse '6' with '7' if it goes wrong. Bonus schematic here. Actually, I did get it the right way round. Yay!

Only one thing for it now - write a program to take photos with a camera. Simple enough: do this in setup(), with 'focus' connected to pin 6 and 'shutter' connected to pin 7:

pinMode( 6, OUTPUT ); pinMode( 7, OUTPUT );

... and this in loop():

digitalWrite( 6, HIGH ); delay( 800 ); digitalWrite( 7, HIGH ); delay( 200 ); digitalWrite( 7, LOW ); digitalWrite( 6, LOW ); delay( 9000 );

And there I had it - an intervalometer taking a photo every ten seconds. Focus 800ms, shutter 200ms, wait 9000ms.

Was that it?

Please excuse the picture quality, I hadn't built the connector for the 7D yet

Obviously not. I now had to turn it into something fancy. To be continued!

Sunday Things

posted in Links by Cargo Cult on Sunday June 10 2012

Splendid transit of Venus from the Japanese Hinode satellite.

Michelangelo was a level designer - designing and optimising sniper balconies for ideal camping opportunities.

Lightning bolt! Lightning bolt!
Stacked star-trail photos from the International Space Station. (With all the timelapses and whatnot recently, did they just get a delivery of dSLRs?)

Bonus Doing away with computers corner:


posted in Media by Cargo Cult on Saturday June 9 2012

So, I braved the mixed reviews and went to see Prometheus - being of the opinion that the original Alien was by far the best of the franchise. Prepared for abject disappointment, I was quite surprised. First of all, a pretty much spoiler-free mini-review:

The Good:

Visually, absolutely stunning. From the sleek, elegantly engineered spacecraft to the clouded, primeval alien landscapes, via weathered alien archaeology - fantastic. Muted colours and visceral impact and understated use of 3D - all positively splendid.

The Bad:

Distinct script and pacing issues - while I liked the (somewhat unoriginal) ideas underpinning it all, it got to the point where several characters could have easily been deleted, tautening up a decidedly flabby cast. When the crew count was declared to be 17, I immediately knew I'd never remember them all - I spotted some genuine red-clad redshirts in there along the way. Some seriously vicious editing and cutting could have improved things dramatically - although having said that, I'd be intrigued by an extended, director's cut - the clunky script is certainly resting upon a Ridley Scott original...

Score? A pretentiously metaphysical four out of five. Recommended, but my obsessive love for the whole 'alien archaeology' thing may have unnecessary boosted my opinions, even if it was more of the Indiana Jones school than Time Team.

Now, on with the utterly spoilery and potentially explosive dissection, after the gratuitous imagery...

Somewhat more expensive than a Firefly-class vessel

Prepared for spoilers? Right then - I wasn't joking. Here we go!

It's about parents. Both having parents, and being one. Of creation, and of being created.

See: David's 'father', Peter Weyland, and his cold, logical engineering of a situation in which Weyland would die. Meredith Vickers' allusion towards Weyland also being her 'father', and her indifference towards his final voyage and her desire to inherit his kingdom. Peter Weyland's preferences towards the artificial, manufactured, technologically perfect David against the human and therefore potentially fallible Meredith. Elizabeth Shaw's loss of her mother then father, then sterility, then forcible caesarian section slash abortion of something deeply horrible within. The Engineers themselves - creating (perhaps accidentally?) a whole new subspecies of themselves, then belatedly declaring that postnatal abortion is the only approach - the exact reason for which is the central mystery of the film.

Still with me?

Dr. Shaw's relationship with her (late) parents is the only remotely positive one, with her increasingly strained Christian faith being her only connection to her mother and father. (How do you reconcile your belief in a benevolent creator with the discovery that your actual, ultimate creators are now a bunch of militaristic, bioengineering bastards intent on exterminating your kind?) Her inability to create, cruelly subverted by those same creators - serious ick.

David allows his effective father to die, and then is 'free' - albeit separated from his body, and now dependent on a human he has already betrayed. He wanted his parent dead, she wants her parents to live.

Did I mention the film is just a little bit pretentious? But then, if you accepted the very name 'Prometheus', you've probably coped okay. The film's Prometheus? The first is the Engineer at the beginning, dissolving himself into clay in order to invisibly direct the evolution of an entire planet's nascent ecosystems. Was this act sanctioned by the whole Engineer culture? Or was it a rebellious attempt at creating new life, not destroying it? Whatever it was, it was enough to justify revisiting their eventual creation time and time again, until a sudden abandonment and change of heart. Central question again.

The basic coordinates provided to the effective children early in their lives? Instead of a welcoming ancestral home, somehow it's metamorphosed into a staging area for annihilation. Is it just our own particular human variant that's been deemed worthy of extinction, or had it become a general policy amongst the Engineers, to rid themselves of their now potentially belligerent offspring?

In terms of setting hopeful familial role models towards today's youth, this film is somewhere between the Texas Chainsaw Massacre and EastEnders. With a definite leaning towards the latter. (In the off-chance that any actual familial persons are reading this, no, not you, you lot are lovely.)

Now, for some science.

Engage 3D specs ... now! (Please excuse the loss in dynamic range.)

I saw someone describe somewhere online that Prometheus' principal failings were the lack of scientific rigour compared with the original Alien. Why, this was vague futuristic fantasy at best, compared with the hard science fiction of its progenitor.

At which point I burst out laughing.

I'd been prepared for inconsistencies beforehand (once again, there's an alien beast that somehow rapidly dramatically increases in mass with no apparent food source, once again there's a deeply confused and incoherent approach to biology, and once again there's a spaceship that's based more around 'ship' than 'space'). But there were some little touches I really appreciated.

Upon arrival at LV-223, the atmosphere was described as "... ~75% nitrogen, ~21% oxygen, few percent argon". Phew, I thought, that's pretty Earth-like - suggesting some kind of photosynthesising biology. "... three percent carbon dioxide." Oh shit. "You'll last two minutes at most out there, so you'll need to wear a suit." High carbon dioxide levels: the worst form of suffocation. Terraforming gone wrong?

Edit 2012-06-15: turns out 3% carbon dioxide is unlikely to kill you - it takes 7-10% for that. Did I misremember, or did Prometheus snatch defeat from the jaws of victory yet again?

Lidar mapping of tunnels was a nice feature, although the typical Hollywood idiocy of the drones' deployers promptly getting lost in a linear environment immediately took effect. I'd actually seen the red lasers in a few promotional shots, and dismissed them as pure atmospheric cheese - the 1970s set-dressing equivalent of blue LEDs. Watching the film, my concerns were soon allayed - this was actual human technology in action.

This time, the biology's still a mess - but it's perhaps intentionally messy and unpredictable. The Engineers have created a bioweapon centred around a virulent outbreak of teleology - a directed evolution capable of offing its targets in varied, vicious (and viscous) ways. Is the xenomorph just one particularly successful variant? I still feel that Alien should be required viewing for anyone designing quarantine procedures on an interstellar mission. Do not remove helmets, for whatever reason. Do not poke at anything vaguely biological. Assume any alien life is potentially hostile. Sadly, this particular fictional universe was left without the educational fictional work that is Alien.

Mentioning typical Hollywood idiocy: guys, I know it's a hubristic corporate pilgrimage unwittingly led by some bright-eyed hippies who've accidentally discovered the secrets of the universe, but seriously. Get someone competent to design your abort procedures, your safety protocols, and invest in some proper support staff. Your geologist should indeed love rocks, but not at the expense of all else. (It's nowhere near Sunshine with its reliance on a scratty few plants for oxygen generation instead of reality's multiply redundant systems, fortunately - at least there's the vague suggestion there are actual emergency backups and procedures to follow, however flimsy or vague.) Also, please shell out for the full software suite for the medical pod - otherwise someone will have to improvise in a distinctly messy fashion. Also, if someone belts you round the head, scampers off for a bit and comes back sporting a fetching scar while leaving bloody footprints, at least look a little bit surprised...

But then, I'm starting to wander. It's a bit of an odd one, this film. On leaving the cinema, it was a three elevated to a four by the visuals. But I've spent the rest of the day thinking about its backstory - and while it's still a definite four, it's a four with utter intrigue for the sequel.

For one, I have a certain fondness for the idea of a stranded, resourceful female academic, surviving surrounded by incomprehensible alien hardware, making her way through unknown worlds in an attempt to tease out reasons and justifications...

Space is Big

posted in Space by Cargo Cult on Thursday June 7 2012

Surprisingly, the weather in Seattle on Tuesday was utterly and totally cloudy - just like it had been for the annular eclipse of the sun a few weeks ago.

Fortunately, NASA's Solar Dynamics Observatory was far up above the clouds, ready to observe the transit of Venus in full.

Dad, are you space?

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I'm not too disappointed I couldn't see it in-person, however - having seen the 2004 one from a decidedly warm and sunny Köln. There wasn't quite the excitement back then - apparently human lifetimes aren't sufficient to see the next one...

August 21st, 2017 should be a good opportunity for eclipse-spotting. I'll be heading somewhere sufficiently far away from Seattle, leaving the clouds far behind...

Tuesday Miscellany

posted in Links by Cargo Cult on Tuesday June 5 2012

My bookmarks-list is roughly two thousand screens long - a vaguely-chronologically-ordered mass of things I've found interesting in the last eight years or so.

Some of the older pages still operate. Picked from vaguely near the middle, have some stuff from the archives...

OMAS SPIDER - 1970s hard diving suit. No idea when I bookmarked this, or why. But I like!

Syd Mead - United States Steel International Syd Mead - United States Steel International
Syd Mead - United States Steel International - what the future was supposed to look like. Syd gives good industrial design, he was just too early.

Lun class ekranoplan - you thought I could post some links and forget some mouldering Soviet hardware that's neither plane nor boat?

Bonus Cup of Brown Joy corner:

  • How to make tea - (British Standard on the standards-compliant manner of brewing a nice cuppa), and
  • Why to make tea - (I'm falling behind on re-educating the inhabitants of these here colonies). via

Advice on seeing transit of Venus in Seattle tomorrow: head for the coast to escape the clouds!