Friday Fings - ancient edition

posted in Links by Cargo Cult on Friday June 22 2012

Another assorted selection of things entirely derived from the bowels of my bookmarks list...

Anyone else feel hungry?
Anatomical Atlases - from the National Library of Medicine's collection. Despite some being centuries old, can unsurprisingly get a bit graphic - so be warned...

I'd love to see it on a dSLR
Splendidly fast lenses - from a German camera wiki. No idea what the article's about, but the pictures are nice... Extra: about the f/0.7 lens used to film Kubrick's Barry Lyndon

Now replaced by a $5 MEMS gyroscope
Inertial Navigator Platform - navigation system originally used on the Lockheed F-104 Starfighter, apparently. Extra: Ms. van Vark has a splendid selection of hardware.

Bonus Morbid Incidents of Mystery corner:

  • Dyatlov Pass incident - fabrication? Fact? What did cause the mysterious and violent deaths of nine hikers on the flanks of a Russian mountain?
  • An abandoned lifeboat at world’s end - a ship's lifeboat, found washed ashore on Bouvet Island - perhaps the loneliest place on Earth. Who was on it, and why?

Sunday Things - happy fun edition

posted in Links by Cargo Cult on Sunday June 17 2012

"Oh, don't mind the tripod. I'm just taking some deeply sinister photos. Carry on!"
City of Shadows - long, black-and-white exposures of a newly post-communist Saint Petersburg, from Alexey Titarenko.

I think it likes me!
Video and Optical - bulbous, insectile machines, monitoring and watching and listening, from Bjoern Schuelke.

I think I just soiled myself. :-(
METACHAOS - feeling cheerful? Sleeping well? Change all that with this frankly horrifying animation - filamentatious, ferrofluidic writhing by way of Silent Hill and Cyriak's worst nightmares, from Alessandro Bavari.

Had enough? Here's an emergency bonus Cuddly Fluffy Animal Corner to aid the recovery.

So cute!
Leopard Moth - from Wikipedia.

I miss these blighters. :-(
Cockchafer Beetle - also from Wikipedia. Do you find its name ... amusing, eh? You disgust me!

Thursday Things

posted in Links by Cargo Cult on Thursday June 14 2012

Top. Men.
Fifty greatest matte paintings - yeah, it's a list, but it's got some weird and wonderful stuff. And Hitchcock was an absolute master of showing things that weren't there, it turns out.

Like a helicopter without the sanity.
Tailsitter Aeroplanes - as with anything in the early Cold War, completely and utterly insane.

FOR SALE: sea view
Last house on Holland Island - since fallen into the sea. Reminds me a bit of the Brighton West Pier...

'Tokamak' - lovely word.
Giant cross-section of ITER tokamak - currently under construction in the south of France.

Bonus Cuddly Robots of DOOM corner:

  • Ping Bot - tiny robot which scuttles around a table, beeping curiously - before releasing a tiny knife-missile which plunges through your sternum.
  • Yellow Drum Machine - samples its own beats tapped out on its surroundings, then samples your own screams as it burrows through your skull.

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:

32KiB of ABSOLUTE POWER

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

LV-002
Splendid transit of Venus from the Japanese Hinode satellite.

cs_firenze1528
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: