Dan's Data letters #146
Publication date: 29-May-2005.Last modified 03-Dec-2011.
Or just put a couch in the computer room
Just read your review on the GTR B-01 HTPC case, you don't mention if it has a remote control, so I assume it does not. I'd've also assumed that would be a pretty important part of a media centre PC in your lounge room (at least for anyone who's concerned about how their stereo components look, anyway)?
I'd like to read an article where you discuss what a media centre PC would actually be useful for, short of playing MP3s. I have run a TiVo here in Melbourne (thanks to the OzTiVo folk), so I doubt one'd be useful for me, but I guess you're supposed to be able to record stuff from TV and archive it... What else?
Abby "darn right I'm Not Safe For Work" Winters
Answer:
HTPC cases practically never come with a remote, but it's easy to add one to any PC these days. Some
TV tuner
cards come with a remote, but they're also available separately. Here in Australia, Aus PC Market can fix
you up with
Niveus,
ATI,
simple,
fancy
and very
fancy iMon, and specific
Media
Center remotes.
Of course, some people just use a regular mouse and keyboard to control an HTPC; unless your living room's pretty large, various cordless keyboard and mouse sets will work.
That last remote I link to above is made for machines running Windows Media Center Edition, which used to only be available as part of a "Media Center PC" bundle from a major manufacturer; now you can get the OS with whatever hardware you like, and it's pretty easy to get it running (Aussies should check this site out) - quite broad hardware tolerance, good interface.
Aussies are still up against it a bit for local program guides and TV tuners (our digital TV standard's subtly different from everyone else's), though it's not nearly as bad as it used to be.
You can also get software to run an XBox as a "Media Center Extender", which connects over a network to a Media Center server with all of your files on it. There are standalone Extenders as well.
In the free-software department, MythTV for Linux is the choice of propellorheads; Media Portal is the Windows XP alternative.
And, of course, there are also "dumb" hard-drive-equipped Personal Video Recorder gadgets, like the TiVo, but without the program guide features. They basically act like a random-access VCR with many hours of built-in storage. Foxtel recently introduced a more featureful box, but it only works with their service.
To be honest, what an HTPC offers on top of TiVo-plus-music, for the vast majority of users, is easy copyright infringement. Anybody who downloads a lot of TV - and that's certainly common enough among Aussies who want their Stargate/Dr Who/Law and Order/whatever one day after it shows overseas, without ads - and wants to watch it in the living room, needs an HTPC. The infringing material may be stuff that you just can't buy - fansubbed anime, movies that never made it to DVD - but it's still, of course, illegal. Then again, so is recording a non-live TV show on a VCR, in Australia (PDF).
You can also legitimately use an HTPC (though, once again, not according to Australian law...) to back up your DVDs and suchlike, but not many people actually do. If they back 'em up, they usually back 'em up onto DVD-Rs.
Dude! Robert Plant is, like, totally behind me!
What is your opinion on 5.1 headphones? I am currently looking at Turtle Beach's Earforce HPA.
Enoch
Answer:
I don't know whether any multi-driver headphones sound very good. The cheap ones, like those ones
Zalman have been selling for a while, certainly
don't. The Turtle Beach ones are also pretty suspiciously inexpensive (though they have considerable fiddle-toy value!);
it's not easy to cram multiple drivers into a headphone that sells for $US100, and comes with a mic and a control
box, and still make the result sound good.
Since at least 90% of the market don't seem to be able to tell the difference, sound quality isn't often a priority (which is a shame, of course, because Turtle Beach audio adapters are generally very good).
Oh, and that "subwoofer" bass shaker thing is unlikely to be more than amusing - to my knowledge, all of the "buzzy" headphones on the market are gimmicky, like the ones I reviewed back in 2001. They're certainly fun, but you're kidding yourself if you think they'll give you The Cinema Experience, or actually add to the realism of games.
I recommend you spend the same money on a decent pair of regular stereo headphones, if you don't already have some.
You could afford Sennheiser HD 280 Pros or HD 515s, for instance (depending on whether you want sealed or open). Save up a bit more and a set of HD 555s could be yours. Or you could save some money, go for old-school looks, and get a set of Grado SR 60s. All good options.
Then, if you feel your surround sound experience is lacking (it won't be, in computer games; plain stereo headphones are the best way to listen to synthesised positional audio), you could start pricing surround processors for stereo headphones. All you need for great headphone surround is two drivers, because you've only got two ears; it's all in the signal delay and phase response, which multiple little drivers in the headphones are not actually very good at reproducing.
Next: Arc welding from a PS/2 socket
I know you're a busy guy, so I'll be brief: I know you can charge a PDA using your laptop's battery via a USB cable, and further, that you can connect said USB cable to a cigarette socket/USB adapter and charge your PDA in the car. The question is, can you charge a laptop using a USB cable connected to the car adapter? Or maybe the other way around - like USB jump starting using your laptop :-)!
James
Answer:
The problem here is that standard USB only delivers 500mA at five volts - 2.5 watts. Even if the voltage isn't a problem
(and it will be - you'd have to step it up to the voltage the laptop battery needs, maybe 7 to 10 volts), an 80 watt-hour
laptop battery (for instance) will take at least 40 hours to charge from a 2.5 watt source. Maybe more like 45 hours.
It's not the 32 hours you might think from simple arithmetic, because charging isn't anything like 100% efficient.
Now, the actual conductors in a USB cable can easily carry quite a bit more than 500mA; you could probably blow a couple of amps through the wire with no trouble, and it'd be easy enough for a cigarette-lighter-to-USB power adapter to deliver that much current (the cigarette lighter from my car draws more than seven amps at 12 volts). So you could get the charge time down.
But laptop makers are never going to bother implementing anything like this, since you can get one-step car laptop adapters (both brand name and, these days, cheaper one-size-fits-many units like this, this or this) already.
Jump starting from a laptop, however, is actually not a totally crazy idea. Not over a USB lead, but you probably could do it with a modern laptop battery or two, if you were careful.
No small cheap battery has the current capacity to start a car, but you can connect a reasonably robust small battery of suitable voltage across a (not-too-)dead car battery, leave it that way for a while to let the big battery build up a bit of charge, then disconnect the little battery and start the car. I've done this with a cheap 7Ah 12V sealed lead acid "gel cell"; you could do it with a 10-cell NiCd pack, too, or with NiMH cells to which you weren't particularly attached.
Modern laptop batteries don't have the voltage for the job, and they're all lithium ion and not at all happy about high currents, but in a pinch you could use two in series with (this is important) a current limiting resistor to stop them thinking they're shorted as soon as you hook them up to the battery.
In a bush-mechanic sort of situation, a few tens of metres of fencing wire (wrap it around a rock for neatness!) would probably do the resistor job well enough.
We can't all have a U2
Whaddaya think about this LED flashlight? Its either a really good deal, or a really cruddy flashlight.
The only thing is that the LEDS cannot be very high power. I don't know how the AAAs would be wired though. In series they would put out 4.5 volts (too much for LED's... unless its resisted down) and in parallel, 1.5V. Which is not enough voltage (I think)....
Mike
Answer:
Really good deal, or really cruddy light? Actually, neither.
Some factory in China's been churning out lights like this for quite a while, now; they're a bit lower class than the CR123-powered versions, because they always run from three AAAs. Some of them have huge lamp arrays - 32 LED versions seem quite common. There are lots of them on sale on eBay.
As you say, the voltage figures don't appear to add up, at first glance. White LEDs want about 3.6V, and three-by-1.5 doesn't go into 3.6 in any good way.
But when you wire three AAAs in series and hook them up, possibly without even a current limiting resistor, to an array of LEDs that draws sufficient current that the batteries scream and beg for mercy, the voltage from the batteries sags, generally to something perfectly acceptable to the LEDs.
This is how basic LED key-ring lights generally work, too. A white or blue tiny-light usually just connects a nominal-3.6V LED directly across two nominal-3V lithium cells, which have giant howling conniptions and, as a result, deliver an appropriate voltage.
All flashlights that use this sort of design are impressively bright from fresh batteries, but fade by the second if left on constantly. They may still be perfectly decent value for money, though, since the current drops as the batteries empty, and the LEDs will still output better-than-nothing light even when the batteries are practically stone dead.
The construction quality of these cheap lights may leave something to be desired, though. Don't be surprised if you have to tweak some contacts to get the thing to stop flickering.
Fills your tank as you drive!
I've been a reader of your articles for some time now, and have noticed a few letters in the past mentioning various fuel savers. Googling reveals the Fuel Saver Pro, Tornado Fuel Saver and Fuel Atomizer 2000.
I spend around $AU60 a week on petrol hauling my 94 Camry between home, work, TAFE and my girlfriend's place (about 650km all up). Anything that saves petrol would be a boon for students like me (besides the obvious first tactic of sensible driving). Those "magic fuel savers" are all a bit too unbelievable (I was told Peter Brock even put his name on one!) [yep - see the end of this column], but this one caught my eye.
In a nutshell, the "Vaporate" is supposed to improve atomisation of fuel by warming it before injection. It's another clip-on device, but around the injectors themselves.
A 20% improvement on the road is fairly drastic, methinks. It is quite different from their own lab results of around 6%. I would say that this is due to the fact that it would be very difficult to replicate the driving environment twice, and unless they conducted multiple blind tests with placebo cars, the drivers would actually try to drive more economically if they knew the rings were fitted to their vehicles.
I was of the opinion that Repco was one of the more reputable auto spares and service dealerships in Australia, but I actually found the Vaporate on their site.
And apparently, a lot of well known service chains are fitting Vaporates.
Out of all the fuel saving devices, this one makes the most sense to my layman's brain, and it is sold and fitted by some fairly reputable names. But I can't help but wonder if this is another gimmick, especially when I consider that if it really worked, car makers would be scrambling to implement it and market the fuel efficiency of their vehicles.
What's your opinion on this product?
Henry
Answer:
Henry wasn't the only person to e-mail me about the Vaporate, after it got pimped on the
highly reliable current affairs show Today Tonight
and in the Murdoch press.
Vaporate say the gadget's been tested at "NATA accredited laboratories", but don't provide the actual raw documentation, or even name the place(s) that allegedly did the tests. I ploughed through the list of NATA organisations - most of which aren't dedicated testing labs - but ran out of energy before phoning around to see whether they did the tests at Cooper-Standard, Delphi Automotive Systems (whose location map implies that their Australian office is perched on top of Uluru), some DoD lab, or somewhere else.
As has been pointed out by people who know more about this stuff than me, there's really bugger-all to be gained from improved fuel vaporisation (right up to blasting the stuff into vapour before it hits the combustion chamber) in modern fuel injected vehicles.
However, I was surprised to learn that at least according to this, 20% might actually be the amount of fuel that some (possibly registerable...) vehicles manage to not burn in the combustion chamber. The figure's apparently more likely to be around 10% (and who knows how current it is), but that's still an awful lot of fuel that escapes proper combustion. A lot of it combusts, at least to some extent, in the exhaust system, so it's not just dribbling out of the exhaust pipe, but still. If this is true, there would indeed appear to be room for improvement, and not just in flame-belching dragsters and smoke-blowing two-strokes.
The question, of course, is whether the Vaporate pre-heating device actually does what it says it does. The inside of the combustion chamber of even a normal petrol engine is, after all, a pretty darn dramatic place to be; spare petrol is heated to several hundred degrees C in there by pressure and radiant flame-front heat, and much of it changes chemical composition as a result, even if it doesn't truly burn.
I'm wondering whether making the fuel a bit hotter before you squirt it in will amount to a hill of beans, here.
Even a 10% fuel economy and exhaust emissions benefit would be worth a Whole Lotta Money, of course. So it's in the inventors' interests to get proper evidence together, post haste, rather than just lean on testimonials and gullible journalists like every other scam artist.
Anyone want to lay bets on whether they will?
(Fuelsaving.info now has a case study page all about the Vaporate.)
But wait - there's more! Click here to go to page 2 of this letters column!
