Do beeswax candles produce negative ionisation? Nope.

This short note is heavily based on Are Ions Good for You, a beautiful exposition of the actual science of ionisation and pollution of the air. There are lots of claims around the internet, mostly by beeswax candle makers, that beeswax candles are “natural ionizers”. The theory goes that beeswax candles emit “negative ionisation” which […]

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Using MOSFETs as blocking diodes

Connecting a battery backwards to an electronic circuit can rapidly do a lot of damage — current will flood through (and destroy) many integrated circuits when powered up the wrong way, and electrolytic capacitors have a famous tendency to explode. For this reason, it’s common to use a blocking diode in a circuit to provide […]

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XKCD’s ‘Click and Drag’ comic in Google Maps form

I just threw together a zoomable view of xkcd’s latest comic using the Google Maps API and US$0.27 of Google App Engine quota: Click and Drag. It helps to find some of the more off-the-beaten-track easter eggs, view it here! If I get enough (i.e., any) interest, I will clean up the source code and […]

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Chilled Mirror Humidity Sensor – Part 1

humidity

One of my hobbies is doing crazy projects — it seems the more useful and practical the project, the less likely I am to be interested in doing it. One project I’m working on is building a humidity sensor from scratch — based on the chilled mirror principle. Chilled mirror dew point sensors These sensors […]

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Deriving magnetism from electrostatics and relativity

Imagine a world where there was no magnetism at all — just electrostatic forces. It turns out that by adding Einstein’s laws of special relativity to that world, and looking at the effects that special relativity has on moving charges, the laws of magnetism appear — just by mashing electrostatics and relativity together. In other […]

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Automatic vs Manual transmission cars

Don’t worry, this post is not advice on how to live your life. Actually, on second thought, it is. Well, no, not really, it’s mostly about cars. And life. Maybe I should start off with my main point: Things which are “easy-to-use” often come with hidden drawbacks. Some examples: Point-and-shoot digital cameras (vs Digital SLR […]

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Where’s the North Pole on Google Maps?

I’ve seen several posts on the internet asking about the North Pole on Google Maps: where is it? Why isn’t there any snow there? Where’s Santa’s house? There’s a couple of reasons why the ice around the North Pole is not shown on Google Maps.

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The Galaxy Nexus PenTile display: a reasoned take on the debate

There has been a lot of discussion on the ‘net about the infamous PenTile display. Lots of sites are throwing numbers around, comparing the ‘subpixel resolution’ of competing phones such as the Galaxy Nexus and iPhone 4/4S. Some commentary has been insane, comparing apples with oranges and declaring PenTile an abomination regardless of resolution. Others, […]

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Rattling Nikon MH-18a charger: how to fix/prevent

During my holiday in Thailand, I was silly enough to drop my Nikon MH-18a battery charger on the floor from a height of a metre or so. As soon as I picked it up, I heard a rattle. When I looked inside, this is what I found: The core of the inductor had broken into […]

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Orewa college requiring laptops: Good. Recommending the iPad: Bad.

UPDATE (August 2014, 3 years since I published this article): I hate to brag, but I told you so… There’s been a story going around the media about Orewa college adding laptops to its compulsory stationary list. Furthermore, Orewa college has recommended the iPad as the best ‘laptop’ to use for this purpose, due to […]

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