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Lichtenbergia

3 December 2007 — dan

The other day I was shining a dangerously bright green laser through a Lichtenberg figure, as I'm sure all of you have done from time to time, and I discovered something interesting.

What?

Oh, all right. I'll explain.

This is a Lichtenberg figure.

Well, technically, the Lichtenberg figure is the feathery ferny shape inside the block of clear acrylic. The shape is a void burned into the plastic by a powerful electric discharge.

A Lichtenberg figure is, in brief, the shape of an electrical discharge. Specifically, it's the shape of an electrical discharge from an area to a point - sometimes over time, but usually all at once.

The acrylic-block type of Lichtenberg ornament is definitely of the all-at-once variety. To make one, you have to shoot your acrylic with a fairly high powered electron beam, also known as a cathode ray.

The electron beam in a Cathode Ray Tube (CRT) television or computer monitor - which, yes, actually is a kind of particle accelerator - delivers electrons with maybe 20,000 or 25,000 electron volts (20 to 25keV) of energy.

That's quite enough to produce considerable X-ray radiation when the electrons strike the inside of the tube - which is why CRTs are made from leaded, radiation-blocking glass - but it's only 1%, at best, of the energy you need to drive electrons even a centimetre or so into a plastic target.

If your electron beam is powerful enough to do that, several seconds of exposure will cause the plastic to acquire a absolutely terrific level of charge. Up in the low megavolts, and with total stored energy ranging from that of a tiny to that of a quite large pistol cartridge.

Then you bring an earthed contact close to one side of the block.

And bang, there's your Lichtenberg figure.

It's been speculated that the feathery tips of the figure are present all the way down to the molecular level.

The world's premiere - actually, pretty close to the world's only - supplier of Lichtenberg figures burned into clear acrylic blocks is Bert Hickman's Stoneridge Engineering. That's one of Bert's in the video above, and I've bought a total of three smaller figures from him over the years, from his eBay store here. This equilateral triangle figure is four inches on a side, and cost me $US24.95 plus postage.

As acrylic Lichtenberg figures get bigger, the energy needed to make them rises, and is soon well beyond what your common-or-garden medical LINAC can manage. This sort of accelerator is not something you can make at home; it's very difficult to get even 1MeV out of a homebuilt unit, even if you're the kind of kid who is only bullied by the members of the football team who didn't know about all the jocks at your old school whose hair and teeth fell out before they died.

You need something like one of the big blighters used to irradiate food. This is why Bert's real monsters are rather expensive.

When high energy electrons hit acrylic, they don't just settle peacefully into the polymer matrix. They actually hit hard enough to discolour the plastic on the side on which the beam enters. This effect is known as "solarisation", because it looks not unlike the discolouration caused by long exposure to ultraviolet radiation (which only has energy of about ten electron-volts).

The electrons actually end up charging the plastic a bit beyond the discoloured deceleration zone. So if you look at an acrylic Lichtenberg figure from the side...

...you can quite clearly see the discoloration and the Lichtenberg figure itself as separate layers.

The solarisation nestles around the Lichtenberg figure like a little bathtub. It fades out around the edges, but those edges rise up around the lightning-shape on all sides.

And this is what I noticed when I was fooling around with my laser.

Shining the laser through the un-solarised part of the figure...

...produced pretty much the effect you'd expect.

But shining it through the solarised portion...

...gave a, much brighter, amber diffusion glow. You can see the beam turning amber as it hits the solarised portion of the plastic.

There's no great mystery about why the beam looks brighter in the solarised area. That seems to simply be because it's travelling through damaged polymer that scatters more of the light.

But the distinct amber colour was a surprise.

Only the scattered light is amber; the main beam's the same colour coming out of the block as it was going in.

Here's the unsolarised side, again.

Another interesting thing about solarisation is that it heals. Over a few years, if you don't expose the acrylic to any more high-energy insults, the orange tint goes away.

The first Lichtenberg figure I bought from Bert was a little two-incher, which I purchased back in 2004. I can't remember whether it had visible solarisation when I got it, but it doesn't now - and a green laser beam stays green all the way through it.

UPDATE: Find some high-res video of acrylic Lichtenberg figures being made in this post!

Posted in Art, Electricity, Nerdery, Science, Strange Tales. 15 Comments »

Fake amp ratings never go out of style

1 December 2007 — dan

A reader brought to my attention the Pioneer HTS-GS1 surround sound system for Xbox 360. It is, apparently, a passable but not fantastic speaker system. But fun is to be found in its specifications.

As I've explored before, consumer speaker systems often have highly inflated power numbers, becuase Joe Average reckons a "500W" system must be better than a "50W" one.

It doesn't actually really matter much what the power rating of a given speaker system is, since most listening even with inefficient speakers is done at only a few watts per channel, and ten times the power only sounds twice as loud. But the marketability of big power numbers has produced various perversions of this reasonably straightforward concept.

The Federal Trade Commission tried to apply the brakes at one point, giving rise to the interesting notion of "FTC watts". The honest wattage description - which the FTC tried to get people to use - was the root-mean-square or "RMS" watt. And then there are others, of variable reliability.

This old chestnut was brought to my attention again by the specs for the HTS-GS1. It's got front, centre and surround speakers which each, as is normal for cheap "home theatre in a box" setups, contain a single small widerange driver - a three incher, in this case. There's also a single subwoofer driver, about six inches in diameter.

The drivers together, if they were unusually beefy with big heavy magnet assemblies, might all together be able to handle a total of 150 watts (with a frequency response of maybe 70Hz to 14kHz). Realistically, something like 50 watts is as much amplifier as you'd be likely to ever need for such a setup.

Pioneer, shamelessly, say the system delivers "600 watts RMS".

(...and 25Hz to 20kHz, of course.)

Then they say OK, we know you wouldn't believe that, and go on to give an "FTC Output Rating" of "155 Watts Total System Power".

(They don't actually have that on the pioneerelectronics.com specs page, which is chiefly notable for its complete lack of any real specifications. But you can find it in the specs on various other pages, like here.)

I, being just plain mean, downloaded the manual (if you'd like to do the same then you'll need to "register", but nonsense data is fine; you don't even need a live e-mail address).

Within, I found this:

There are those two power ratings again, broken down by channel... but what's that below, under "Power requirements"?

Only 41 watts?!

Glory be, it's a miracle! This speaker system can output 3.78 times as many absolutely genuine FTC-certified Super Muscular All-American Watts as it takes to run it!

Quick, someone hook up arrays of HTS-GS1s to the power grid! The world's energy problems are solved!

Don't reward this kind of crap by buying these products.

No system-in-a-box with small single-driver main speakers and a six-inch sub is ever going to sound very good. It may be easy to set up, but you're paying for a bunch of portable radio speakers plus one tuned-for-muddy-thumps mid-bass driver.

Far better to buy a modest stereo amplifier and a couple of decent bookshelf speakers. That'll give you reasonable sound from in front of you, which in my opinion is far better than crap coming at you from all directions.

I don't mean to single out Pioneer in particular here, either. Every system-in-a-box that looks like this, whether it's made for a game console or for a home theatre, is going to be just about as bad.

If you only pay $US75 or something for the whole setup then it may be tolerable, for games at least. But even then, I'd rather spend the same money on stereo gear from a garage sale.

Even if that gear doesn't promise to make power out of nothing.

Posted in Electricity, Music, Scams. Leave a Comment »

My new favourite flashlight

24 November 2007 — dan

There are quite a lot of flashlights in this house.

So, of course, I had to go and buy another one.

It only cost me ten bucks from this eBay seller. And it's possible that it's actually a genuine antique.

Which is a bit unusual, for an electrical device. Especially one that works.

The generally accepted definition of an antique is something at least a hundred years old, and flashlights that looked much like this one certainly were on sale a hundred years ago.

The first portable electric lamps appeared in the last few years of the nineteenth century. The first commercially successful one was the boxy Acme Electric Light, in 1896. But the easier-to-hold tubular flashlight was first sold commercially, by one Conrad Hubert's Ever Ready Company, in 1899.

This light probably isn't nearly that old, but it's still got the thick "bullseye" glass lens that all tubular flashlights had for the first decade or so of their existence.

(If you ask me, "bullseye lens" should only be the term for the concentric-circles fresnel lens, as seen in lighthouses and stage spotlights. This kind of flashlight lens could more correctly be called a "dome". But "bullseye" seems to be the most common term. "Walleye lens" seems to be another term for the same thing.)

The bullseye lens was not a good design.

It's either planoconvex (flat on one side, convex on the other) or, as in this case, slightly concave on the inside and much more convex on the outside. Either way, the lens gives the flashlight a very broad beam.

The beam width is at least 60 degrees, for this light, and it has no central "hot spot" at all. It's quite unlike the output of the more usual kind of incandescent-bulb flashlight, with a thin flat lens on the front and a relatively large reflector around the bulb.

A super-wide beam is great for seeing where you're going, but useless for seeing anything at a distance. This was quite disastrous for flashlights a hundred years ago, because they weren't very bright at the best of times.

This light was probably made to take a tungsten-filament bulb, but those weren't very efficient until the coiled-coil filament was introduced in 1936. Earlier still were the even dimmer, more fragile and rather inconsistent carbon-filament bulbs. And the old batteries had lousy capacity, and lousy current delivery, too.

So overall, old flashlights needed all the light-concentrating help they could get.

But instead, everything that wasn't big and boxy like the Acme Electric Light got a fish-eye lens.

It's been postulated that the bullseye lens was so popular for so long because consumers thought it concentrated, rather than dispersed, the light from the bulb. At a glance, you might think that - look at the bulb through the lens and it appears huge, just as it would if it were in the middle of a big reflector.

But with a bullseye lens, the bulb appears huge from every angle, because light's being thrown everywhere.

I suppose people were accustomed to wide-angle illumination from fuel-burning lanterns. The flame from a lamp with a wick is too large a light source to be effectively concentrated by a reflector of readily carryable size, and there are further problems with just getting a reflector in there, next to a hot and possibly smoky naked flame.

Directional lamps did have reflectors - miners' acetylene carbide lamps are an excellent, and surprisingly practical, example - but they still threw a very wide beam.

(Which, in the case of the carbide lamp, was quite respectably bright even by modern standards. A small "helmet" carbide lamp can easily throw as much light as a five-watt incandescent bulb, and it could do it for several hours. Five watts for five hours is 25 watt-hours; that's about the same amount of energy as you'd get from two modern C alkalines. Carbide lamps are little more than a hundred years old; they were quite revolutionary in their day, and far superior in light output and safety to kerosene or other oil lamps. Carbide lamps were still perfectly capable of burning your house down, though; you could only do that with the new-fangled electric lights if you really tried.)

Bullseye-lens flashlights hung around long after the common availability of modern large-reflector, flat-lens lights - note the Prohibition-era hip flask in the shape of a bullseye flashlight here. So it's quite possible my little light is only about seventy years old. That's still pretty impressive for a device that's still useful today, though.

A nice one of these lights would be an Eveready Daylo, or something. This one's a brandless version with no decoration, cheaply made from sheet metal, so it's probably worth nothing to a collector.

Like other lights of this size and vintage, this flashlight wants a weird battery - a 2R10 "Duplex" or "2B". That's a three-volt, two-cell battery that's apparently about 75 by 22 millimetres in size, and still available today, if you're really dedicated and/or willing to take apart another battery. The 2R10's dimensions make it quite magnificently incompatible with every common battery today.

A 75mm-long battery must have been a pretty tight fit in this light, though, because it turns out that a modern 18650-size (18mm wide, 65mm long) lithium cell fits very nicely, especially if I screwed the bulb all the way in.

But, to do that, I did need a bulb.

The bulbs this old light uses, fortunately, are quite standard. They're the same miniature Edison screw (MES) type that survive in small cheap lights today. (Though no doubt not for much longer, since LEDs are now clearly superior.)

An odd flattened-bulb vintage MES lamp came with the flashlight, but of course did not work any more. I had a cheap push-light doodad sitting around waiting to have some RGB LEDs put in it, so I harvested the bulb from that. It was meant to run from four 1.5V cells and so should have been reasonably bright from the roughly four volts of the 18650 cell, but it was actually quite dim, and died after not many minutes of use.

So I got an Eveready MES bulb for "5D" flashlights, rated at 0.3 amps at 6.2 volts, and tried that. The flashlight's much brighter now, though it's probably running its bulb at rather less than half of its 1.9 watt rating.

The low voltage makes the flashlight's output very yellow, which I find quite pleasing in this age of blue-white LED flashlights. The light colour's probably quite similar in hue to the light from its original lamp, but brighter. It's perfectly usable as a night-time seeing-where-you're-going light.

I wasn't expecting it to be this easy to make this light work. I thought I'd have to hack some LEDs into it, or something. But it turned out to be easy to fix, in a more authentic manner.

It's been foggy, lately, and now it's getting dark. I believe I may procure myself a Webley revolver, and sally forth with my newly purchased "hand-torch" to investigate the night-cult that drunkard spoke of in the inn, before his fellows silenced him so brutally.

I'm told that a torch whose light is feeble may be a blessing.

There are things which are best not clearly seen.

Buying one

The eBay dealer I bought my bullseye-lensed flashlight from now seems to be dormant, but similar items show up on eBay pretty frequently. They can be a pain to find, though.

This search right here finds anything that could be a real old bullseye flashlight and filters out a lot of useless results, but it's not quite the same as the actual search I've got saved and sending me e-mails just in case a cheap light even prettier than the one I've got shows up. That's not because my search is a trade secret, but because there's a limit to the length of the search string you can link to via the eBay affiliate thing. The full search string, for your cutting and pasting pleasure, is:

(old,vintage,antique) (torch,flashlight) -paisley -"pipe lighter" -"torch green lighter" -"green flame" -"torch lighter" -blow -heat -kero -kerosene -kerosine -projector -patent -bulbs -pin -pins -bearers -guitar -spirit -blowtorch -cutting -bead -"ornamental lighter" -"ornamental gun"

To throw an even wider net, it's easy to search for flashlights in the eBay "collectibles" category (here on eBay Australia and here on eBay UK, both with the added search term "torch" to find Commonwealth-usage listings and clutter the results with ancient rusty dangerous blowtorches). But the results in that category aren't very good; you get a lot of brand-new LED lights and plastic crap from the Seventies. People selling bullseye-lensed lights unfortunately seldom describe them with a handy searchable word like "bullseye" or "dome", so you pretty much just have to scan the thumbnail pictures until you find one.

Do the same search in the "antiques" category (here on eBay Australia, here on eBay UK; I've left "torch" off the search string this time to avoid zillions of hits for tiki torches and candelabras) and and you'll find a lot more genuinely old flashlights. "Antique" bullseye-lens lights that aren't just a pile of rust with a lump of scratched glass in the middle, though, are generally pretty expensive.

Some of them are very beautiful, though. The "bicycle light" type that's a wooden box with a handle on top and a lens on the side is particularly appealing, especially after a dab of wood polish. Box-lights usually have plenty of room inside for modern batteries and lamps, too, so you probably won't even need to disturb the dreams of the world's flashlight collectors by destroying the old fittings in order to shoehorn in a pink LED and lithium battery.

Posted in Electricity, Nerdery, Toys. 7 Comments »

Guardian Angel (battery)

11 November 2007 — dan

There I was, innocently reading Engadget, when I struck this post about how "Exradia suggests that iPhones could warp brains".

Exradia's argument is that cellphone radiation is harmful (which is dubious at best, but let's continue), and that the iPhone is particularly dangerous. That's because the iPhone battery is not user replaceable (not without soldering skills, anyway), which means, drum roll please, that you cannot buy one of Exradia's special after-market radiation-reducing batteries for an iPhone.

On the face of it, Exradia's claims sound like poppycock.

Let's assume that cellphone radiation is bad for you. Well, that's a shame, because mobile phones depend for their operation upon the emission of that radiation. A phone that cannot emit pretty much exactly that same radiation is a phone that will not work. Wrapping your body in earthed flywire is the only option, if you insist on still using a mobile phone.

So I was interested to hear Exradia's explanation of what their "Angel™ batteries" (available for all major brands!) were actually supposed to be doing.

That explanation can be found here.

Apparently, "Exradia's Angel™ technology superimposes a random noisefield on the bio-effective man-made EMFs that are typically emitted by cell phones and most other digital wireless devices. With Angel™, the body (cells) detects only randomised signals that cannot trigger a cell's response and therefore cannot be harmful to cells."

I've heard much worse scientific word salad than that, but this still sounds like nonsense to me. Exactly how a battery is supposed to be changing the output waveform of the phone's radio at all is a pretty big stumbling block; does the battery have its own antenna? If it broadcasts random noise in the frequency range in which the phone operates, wouldn't the phone just turn up its own radio volume, if possible, to compensate?

I could go on, but I'm just speculating. The Exradia explanation isn't clear enough for anything better.

Exradia's "Bioeffects of EMF" page refers to a 2000 University of Washington study that found that microwave exposure fragmented DNA strands in the brains of rats. Apparently superimposing a random signal on that field was somewhat protective. Nobody else in the world has been able to replicate these results - quite the opposite, in fact - but that hasn't stopped vendors of various allegedly-noise-emitting anti-radiation talismans from cashing in.

Hunting more info on this subject led me to The EMX Biochip™, and that led me... straight back to Exradia, who're currently hit number 1 for "EMX Biochip" despite not having that string anywhere on their site. According to this page, Exradia bought "the EMX technology".

What, exactly, the EMX technology actually is will remain a mystery, even if you read Exradia's "Science Whitepaper" (PDF). Not the slightest clue is presented as to how a component in a phone battery can semi-randomise the radio output of a phone.

If the magic batteries don't have their own antennae, all they could possibly do is try to inject RF noise into the phone through the battery terminals, hoping that it'll make it through the circuitry to the antenna without interfering with anything or being eaten by other components (hint: that won't happen), or find some resonant component before the antenna that can be used as an aerial in the absence of a proper one.

But here I am again, speculating. I'm forced to it by the vast windy wasteland that is Exradia's explanation of what the hell they actually claim to be doing.

The Exradia technology page does go on to say "Angel™ has been proven to eliminate biological effects in all instances in which it has been tested in labratory research."

If you're now waving your hand in the air and saying "Ooh! Sir! Sir! I bet that research cannot be found anywhere on the Exradia site!", then you get an early mark.

Everybody else now has to read this post on the Quackometer blog, which points out that Exradia seem to be a pretty serious business entity (compare the late and not very much lamented Batterylife AG), but which also expresses mystification about how the heck the Exradia/EMX technology is even supposed to be able to do the job they say it does. Never mind whether the job needs to be done at all.

The Quackometer blogger, Andy Lewis, managed to read more of the EMX intro page than I did before his brain seized up. He discovered that the EMX "technology" actually, on that page at least, claims to be influencing not the high frequency radio output of the phone itself - which, I remind you, is what has most cellphone danger enthusiasts hot and bothered - but the low frequency output (way down in the audio range) of other electronics in the phone, and the low frequency modulation of the microwave output.

Andy then makes the obvious point that if low frequency EMR is the problem, just squelching the small amount of it that comes from mobile phones is completely meaningless - every urban human is bathed in low level, low frequency EMR for most of their lives.

(And yet, when you control for other risk factors, even people who live under power lines - let alone the rest of us with our TVs and computers and clock radios - don't seem to get any disease more often than other people.)

I was surprised about the whole low-frequency thing, because Exradia's tech page specifically says "cell phones and other digital wireless devices emit man-made EMFs...". If they were concerned about low frequency emissions, they wouldn't have said "digital wireless devices", which in this modern world all emit far more high frequency, gigahertz-range, radiation than anything else. And why would they have referred to that study of microwave effects on DNA if that wasn't their concern?

So it would appear, based on the incoherence of the arguments presented for it, that the Exradia Angel battery is as silly as the Q-Link pendant (which Andy mentions in passing).

It's not as obviously silly, and it does at least do something (power a phone). And I am grateful, don't get me wrong, for the fact that Exradia never use the word "quantum".

But the Angel battery's special reason for existing is questionable, its ability to achieve that goal is doubtful, and even the people whose motto is "we think everyone should have one" (of course you bloody do, you're bloody selling them) cannot explain what it is their product is even supposed to do.

[UPDATE: A few months after this post, Exradia ceased to be, joined the choir invisible, and screwed their creditors.]

Posted in Electricity, Scams, Science. Leave a Comment »

Secret Life Of Machines update update!

31 October 2007 — dan

A new, better-than-ever opportunity to watch Tim 'n' Rex's outstanding Secret Life Of Machines (previously mentioned here and here) has arrived:

The Exploratorium science museum has made every single episode available for straightforward download from their site!

[UPDATE: Or, at least, they did. There was unexpected demand, so they took the files down again. Their Webmaster quietly reinstated them in a different location for a while, but then word got out and he took 'em away agin. Never mind, though: I got them all, and made a torrent! The Exploratorium direct-download page came back up after the initial rush was over, so you should be able to get the episodes there now - but you might as well still give their server a break and use the torrent.]

There are QuickTime streaming versions which seem to be broken at the moment, but never mind those - the ones you want are the "iPhone" versions. They're standard iPhone video format (480 by 360 pixel, MPEG4 video, 128 kilobit AAC audio, M4V container), which is playable on PCs without much messing around. If you don't happen to have the right codecs and don't want to faff about installing QuickTime or something, just play 'em with the all-in-one VLC media player.

(The iPhone format is also 30 frames per second, not the 15fps of the old iPod Video format.)

I presume these rips are from the DVD edition, because they look a lot nicer than the VHS rips that've been doing the rounds before now. And they're less than 192Mb per episode, so all 18 episodes will fit with room to spare on one DVD-R.

Posted in Electricity, Movies, Nerdery, Science. 12 Comments »

Ecowatts: Place your bets!

17 September 2007 — dan

The "Ecowatts Thermal Energy Cell", according to the entirely reliable Daily Mail, produces far more output energy (in the form of hot water) than you have to put into it in electricity.

Ecowatts, according to the Mail, have the support of one Jim Lyons of the University of York, who is a real person with real engineering qualifications and says he's tested the device and been amazed.

Ecowatts say on their site that "the technology has been verified by UK Universities and Measurement Organisations"; needless to say, they don't go on to name any of them. There's not even a mention of Mr Lyons.

Ecowatts gave the University of York fifteen thousand pounds to do the research. The person they were listed as giving it to was apparently not Jim Lyons, though. I doubt this is a plain CorporateWhore situation, but who knows.

There's a lot of room for improved efficiency in most hot water systems. The standard arrangement in which a lot of water is made hot and kept in a tank waiting for use is bad enough. The fact that people then "shandy" the hot water with cold water when they use it for bathing is even worse.

But one place where efficiency really is perfectly fine is the point where, in an electric water heater, the element heats the water.

That stage, like all other electrical heating, is as close to 100% efficient as makes no difference. (A tiny amount of the input energy to a hot water heater element is lost, for instance as sound.)

So a device which, as Ecowatts say, "converts electrical power into heat at an efficiency significantly greater than that of a conventional immersion heater", is by definition an over-unity device. Being able to get "150 to 200 per cent more energy out than we put in, without trying too hard", as Mr Lyons says in the Daily Mail piece, takes the heater straight into the realm of practical perpetual motion.

Because I have a passing knowledge of the 100% historical failure rate of these sorts of things, I am completely certain that this newest device will fizzle out just like all of the others.

I'm hoping for a more dramatic denouement this time, though. Not just the usual sad bilked investors - I want revelations of corruption and academic arguments!

It probably won't be as much fun as Firepower, but it could still be good for a giggle.

UPDATE: The end of the Daily Mail piece mentions that this gadget was previously being hawked by a company called "Gardner Watts". I've found this piece from the Daily Telegraph which talks about it. It's from 2003.

Once again, the claims were apparently verified scientifically - by one Doctor Jason Riley of Bristol University, who is another real person.

And the claims were bigger that time. According to the Telegraph, the 2003 version delivered "energy gains of between three and 26 times what had been put in".

The 2003 Gardner Watts "cell" was going to be on the market "within two years".

But here we are, four years later, and still... nothing. All that time, and not one published paper, let alone a working product.

And not even a nibble from those cynical bastards at the Nobel Institute.

Posted in Electricity, Scams, Science. 7 Comments »

#000000 - for the environment!

27 July 2007 — dan

A reader pointed out the questionably power-saving Blackle to me a couple of days ago; now it's hit Slashdot.

In brief: Yes, a CRT monitor uses more power when it's displaying light colours than when it's displaying dark ones. But no, there isn't likely to be any significant difference if your computer has an LCD screen.

A bit of searching (with evil white-screened Google...) turned up this page on the blog of one Mark Ontkush, who started the whole thing.

A reader of the first-mentioned post reports he actually tested a 19 inch CRT and LCD, and found, as you'd expect, that the LCD used less power in the first place but changed its power consumption not at all with the content of the image, while the CRT dropped from 83 watts to 60.

It's conceivable that an LCD might consume slightly different amounts of power when displaying different images, since it takes power to turn on all of those zillions of thin film transistors, three per pixel, that make up the image.

It might even use less power for darker images. I used to be under the impression that when an LCD pixel was fully "on" it was black, but that actually only applies to the old twisted nematic kind of LCD. Most LCD screens these days use newer flavours of LCD technology in which a fully energised pixel is white.

Ontkush's site also has this page, in in which a low-brightness design palette is put forward for much the same reason, and in which a (different) reader finds that the darker colours do indeed seem to reduce an LCD's power draw... by a lousy three watts.

There are some cleverer flat panels these days that modulate their backlight brightness according to the image being displayed. I don't know whether any computer monitors do it (I think it's still a home theatre thing), but it makes sense, and would cause darker images to consume less power.

Most LCDs these days have such super-bright backlights that to use them in most indoor domestic situations you should turn the brightness down to minimum manually anyway. Variable-brightness backlights probably won't be able to go any dimmer than that minimum manual brightness. LED-backlit LCDs (which are still very rare) may be able to go further, though; the minimum brightness at which a cold-cathode lamp will continue to work properly is quite a bit higher than the minimum brightness for a bank of LEDs.

The reader who brought Blackle to my attention had it brought to his attention by that internationally recognised bringer of totally reliable information, a multiply-forwarded e-mail. That particular e-mail, or one very like it, can be found all over the Web now, including the allegation that "Google created a black version of its search engine...".

Blackle is not, of course, actually a Google project. The domain's registered to some outfit here in Australia.

I've never been able to figure out how it is that these sorts of aimless fabrications get tacked onto much-forwarded messages. Somebody somewhere along the line had to make up the "Google created" factoid all by himself and add it to the text... but why?

Snopes is full of stuff like this. Sometimes it's obviously someone just making up a story to go with a funny picture because it entertains them to start a hoax or they want to reverse the political slant of a forward they just received, but just as often there's not even that much justification.

It's like a model of evolution. Messages mutate randomly as they pass through different people's hands, and the most appealing ones are then more likely to be forwarded-to-all by everyone's dimwitted coworkers and dotty old relatives.

(Thinking you're doing something For The Environment by darkening the palette on a Web page is also, of course, a pretty good example of slacktivism.)

UPDATE: I've got a power consumption meter now, and I've used it to see how much juice my giant Dell monitor consumes. The screen brightness setting made a big difference; what the screen was displaying made a small one. Read all about it!

Posted in Electricity, Science, Strange Tales. 4 Comments »

Motorvation

19 July 2007 — dan

The first article I ever read on the most excellent Evil Mad Scientist Laboratories site was their one on how to build a homopolar motor.

Go there. Check it out. Build one. It's ridiculously easy, and it works remarkably well. And, unlike some other unlikely motor designs, it's unlikely to rip skin off your thumb and then become red hot.

Unsurprisingly, homopolar motors have become something of a GooTube phenomenon, and there've been some innovations.

The Evil Mad Scientist version of the motor has four parts; one battery, one screw, one magnet, one bit of wire.

This can be reduced to three parts by making the magnet static and turning the wire into the rotor:

The "roller" variant.

An elegant spiral version.

The screw type, turned upside down!

Balance this one properly and it could be quite impressive. Using hard disk components is definitely a good way to start.

This one's quite imposing, though the timidity of its operator suggests it's not very well balanced, either.

OK, now this is just showing off.

Before this newfangled fad for homopolarity, there was another "world's simplest motor" that also needed only three components, if you chose those components carefully (it's mentioned on the Evil Mad Scientist homopolar page). Kids who want to get a solid C on their science project can buy a kit to build one.

The old "World's Simplest" motor is considerably more complex than the homopolar motor, but it's also much closer in design to a standard commutated DC motor.

Here's a home-made one in action:

And here's how to make one: