Quick Circulation post/Mitochondrion progress

I wandered off to Circulation, caught up with lots of people that I don’t see often enough, made new friends, did a small amount of tissu, trapeze, yoga, slack line (hard), slack rope (ridiculously hard), and gave the Mark 4.2.2 it’s first public showing. It looked a bit like this:

For the Mark 4.2.2, I’ve switched all the pattern generators from red, green, blue to hue, saturation, and brightness, with saturation generally whacked all the way up as far as it goes. I got over myself and gave it to various people for a spin. They didn’t break it and I got to see it from the outside for once.

That’s Keir having a spin in the marquee. I’m sure the first thing that comes to mind is the refresh rate. 20 ms per update, 44 frames in the one loop in the photo, from which we can calculate that he’s spinning it at 720 degrees per second and that the camera shutter was open for half a second. What, that’s not the first thing that comes to your mind?

Having had a chance to sit and watch other people spin it, it’s clear to me that the new code generates all sorts of patterns, most of which I thought up while sitting in front of a laptop. Some work visually, some don’t, so the next stage is to work out what patterns and responses actually look good while spinning and winnow down the random spray of colour and light into a better selection. Oh, and tweaking the slower patterns to remove the bottlenecks in the generator code (floating-point divides and calls to the random function, as you’d expect), with the goal of getting the update time down to under 10, maybe under 5 ms, for bonus complexity, more interpolation in the patterns, and smoother visual flow. And more integration of the motion sensors with the patterns. And a few other things. But it’ll do for now.

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7 thoughts on “Quick Circulation post/Mitochondrion progress”

  1. Looking great!

    I’m genuinely surprised you hadn’t already jigged it into a swing-head lathe in a dark room to tweak the patterns under controlled settings 🙂

  2. FYI, Lynelle at the Palmerston North/Massey University Fire Club also made her own LED-driven glow stick (there’s a photo of it in action on their blog, as well as some photos I took of it in action last weekend). From what I could tell hers had two patterns (all on steady; all blink at a constant rate in sync). I mentioned you’d made something similar, but more programmable, and she was very envious. (The main observation I’d make is that her hand grips — which seemed to be two elastic loops loosely holding the stick — gave a different variety of motion, which made the “all on steady” quite interesting, at least in terms of photographic light trails.)

    Anyway I’m led to understand that you have a standing invitation (at least from Lynelle!) to go visit the PNMUFC with the Mitochondrion at any time… 🙂

    Ewen

  3. BTW, random photographic tips: it’ll look more dramatic when photographed against a very dark background. If you want the person to show up clearly (rather than just ghosting) then you’ll want to use a flash, ideally at the end of the exposure (“rear curtain sync”) so that the blur is leading up to the position they’re clearly shown in. If you don’t want the person to show up, then keeping the environment as dark as possible, having them wear as much black as possible, keeping the LEDs in the device away from their body, and possibly under exposing the image a bit will help.

    Depending on the pattern, and spinning movements, exposures anywhere from half a second through several seconds can look good. The longer the exposure is, the more it’ll cry out for a tripod or other steady shooting platform.

    Ewen

    1. No, really?

      *ahem*
      Secret Missions – Revealed

      Anyway, the pic above was a quick one from an SGS2 at god-knows what time of the morning, mostly just to prove that that was what I was up to. I had a quick sesh with David from Southern Exposures as his batteries died. His pics aren’t up yet, but yeah, it takes substantial effort to get a good picture of a scene with so much motion, contrast, and hue.

      1. FWIW, that wasn’t meant to be “that photograph could have been better”. It was meant to be “you’ve made this cool thing that’s somewhat tricky to photograph, so perhaps I could help make it look even more cool”. As you say, it takes substantial effort to get a really good picture. Apologies if it didn’t come across that way.
        Ewen

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