Travel: New Zealand – Tiritiri & Rotorua

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Painting with Light 1.3: New Designs

Follows Painting with Light 1.2: Patterns Emerge

As much fun as this has been to play around with, the print area is just too small! Using SketchUp I’ve come up with some designs for a new scaled up version using MakerBeam and pulleys (instead of threaded rods like current design). Printer04

This should give a total print area of about 250mm (as opposed to the 50mm I have now). If I put an SMD LED inside a small enclosure with a tiny 1mm hole, I should be able to decrease the width of the lines to further improve resolution as well. I figure at the moment the lines are about 3mm wide and the print area is 50mm wide. So that’s a resolution of about 17×17 pixels. With 250 x 250mm bed and a 2mm wide line that will give a 125×125 resolution, or 250×250 at 1mm wide lines.

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Painting with Light 1.2: Patterns Emerge

Follows Painting with Light 1.0: Getting Started


Following my initial attempts, 5mm LEDs have been replaced with a set of 3mm LEDs to provide a little bit of extra resolution. Light pollution has been decreased a bit too by painting the bottom of the LEDs and some of the topmost surfaces of PCBs, stages.


Which makes some fun patterns after the break!

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Painting with Light 1.0: Getting Started


Long exposure photography has always interested me, as have stepper motors and their various uses though I know nothing about either of them. I came up this project to try and bring the two interests together. When finished I’m hoping to have something akin to projects like this, this and this that can draw recognisable pictures with light.


Read more after the break!

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Travel: New Zealand – Central North Island


I’ve returned from a 10 day round trip of New Zealand’s central North Island. This was totally an awesome trip and I strongly recommend trying it! You don’t need much time and will get to see a lot of what the area has to offer

Central North Island Trip

Pretty pictures after the break

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Graphing the Collatz Conjecture


The Collatz Conjecture (also known as hailstone sequences or the 3x+1 problem) is a problem in Mathematics first proposed some 60 years ago. It goes like this: Pick any positive integer. If the number is positive, we halve it. If it is odd we multiply it by 3 and add 1. Keep applying this rule until you reach a repeating sequence of numbers. For example let’s start with either of the numbers 3 or 20 and apply these rules.


As long we follow these rules our numbers will go up and down for a while before reaching a repeating sequence (4 -> 2 -> 1 -> 4 -> 2 etc). Once we reach 1 we tend to stop counting. This starts slow but gets a lot cooler after the break.

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Understanding the Enigma


In World War II the German Military used a rotor cipher machine commonly known as “Enigma” to communicate in secret. Because of the seemingly random way it encrypted messages it was an extremely effective piece of equipment during its heyday. Enigma went through many iterations each of which drove interesting developments in mathematics and computer technology.

An Enigma I. From Crypto Museum

An Enigma I. From Crypto Museum

For a while I’ve been fascinated by the Engima Machine and have wanted to learn more about it. Having decided the best way to approach the daunting subject was to just build one I chose Microsoft Excel as the initial medium to reconstruct Enigma. I’ve created this post to go with it as a kind of Enigma primer, covering with broad strokes the mechanisms that make Enigma work.

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12 Months of Movies – 2013


For the last year I’ve been recording details about every movie I’ve watched. This only includes movies I haven’t seen before, or haven’t seen for at least 3-4 years (such that it’s kind of like watching it for the first time anyway). In addition to when I watched it, I’ve also recorded details such as when the movie was released, it’s IMDb rating, the genre keywords associated with it and other similar bits of info. The list of movies is embedded below, but can also be viewed at googledocs if it doesn’t load.

The rest of this post is a quick look at what my favourite and most hated films watched in the year were. It is a good representation of the kind of movies I watch, though I realised while writing that it does gloss over certain things. Since I was only recording the first time I watched a movie it does skip a lot of things. For example there is no mention of the fact that I must have watched Iron Man 3, The Avengers or the last two Fast & Furious movies 3-5 times each in 2013.

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A Month on the Styx: October 2013


What I’ve been playing

  • GTA V: Finished story mode after about 45 hours play time. The campaign is an epic feat of storytelling. I was fairly skeptical going in, but Rockstar nailed it. Some aspects of the game I thought could be improved but overall it’s an amazing game. 9/10.
  • Dishonored: Only 5 or so hours in so far. Liking this a lot. TBD/10.
  • Super Meat Boy: This game is so hard but I love the sheer simplicity of it. Music and artwork are terrific too. 8/10.

What I’ve been eating

What I’ve been watching

  • Toy Story (1995): Fun, but different to what I remember. Was interesting to get all the jokes meant for adults I didn’t get as a kid. 6/10.
  • Carlito’s Way (1993): Al Pacino crime drama set in 70′s NYC? Yasssss. 8/10.
  • Agents of S.H.I.E.L.D. (2013): It’s breaking my heart but I’m not really liking Agents of S.H.I.E.L.D. at all. It has a strange soap opera vibe to it and all the characters are tacky overused archetypes. I had a strong urge to punch my TV at various points in the fifth episode. 5/10.
  • Adventure Time Season 2: Batshit insane as ever. Love this to death. 10/10.
  • The Incredible Hulk (2008): Meh. Wasn’t really a fan. 5/10.
  • Moneyball (2011): I liked the movie, was definitely well made but a lot of it was lost on me considering I know absolutely nothing about baseball (apparently it’s the one with the bats that isn’t cricket?). 6/10.

What I’ve been doing & upcoming projects

How To: Using Relays and an Arduino to Control the Lights


For my plant growth project I want to control a fluorescent bulb (among other things) with an Arduino. Fluorescents can’t exactly be powered by the measly 5V available on an Arduino so instead we’ll be using a relay to control mains power. I’ve structured this post as a tutorial so that hopefully it might help anyone learning to use relays with an Arduino.

Safety Warning: This is dangerous, mains power isn’t to be trifled with. If you don’t feel comfortable playing around with mains wires then don’t try it! There are kits such as the Powerswitch Tail Kit that will do this job for you. You can get the 120VAC model prebuilt, but it looks like you have to put the 240VAC model together yourself.

Parts list:
  • 3m Extension cord (must be the 3 prong variety)
  • 1K Resistor
  • 2N2222 Transistor
  • 1N4004 Diode
  • Appropriate mechanical 5V relay (250VAC rated for Australians)
And of course
  • A lamp to test with
  • An Arduino to control it with

Assuming you already have an Arduino and other bits and pieces lying around this is a pretty cheap project. The most expensive part is the relay which will only set you make $10 or so.

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