Dan's Data letters #48
Publication date: 9-June-2003.Last modified 03-Dec-2011.
LCD lag?
I have been using an Acer AL732 17" 16ms LCD for about 1 month now, and while I agree with everything you said about LCDs, you didn't say anything about the mouse refresh.
I found switching from a CRT monitor running my mouse at 200Hz to an LCD made the mouse felt very very laggy. Nowhere near as smooth as it was on the CRT. Even a month later I am struggling to bear it, and will be switching back to CRT very shortly. Did you find this as well? Just wondering, because if I had read a review that mentioned this before I purchased this monitor, I would have definitely had thought twice.
Mark
Answer:
Changing the monitor shouldn't have done anything at all to the actual mouse sample
rate, and a fast-response-rate LCD like that Acer shouldn't cause much blurring in most
situations, so the only thing I can think of is refresh rate.
If the LCD was running from only a 60Hz vertical refresh rate (which, according to the Australian Acer site, is all it supports in digital-input mode; the main acer.com page for it doesn't mention refresh at all), then the mouse position would only update 60 times a second.
The monitor would look superficially exactly the same as a higher refresh LCD - because LCDs don't flicker, regardless of the rate at which the screen's updated - but your effective mouse sample rate would be 60Hz. Even 75Hz, the fastest vertical refresh rate the monitor can accept, would probably be noticeably jerkier. That might account for the "lag" you're seeing.
Dummy batteries?
There are many devices in our lives that run off of batteries, and only batteries. 1 AAA, 2 AA, 1 C, 1 AA - the combinations of batteries are endless. Many of these devices do not have a convenient DC plug on them to convert them from battery only to AC power. So the only way to "convert" them off of battery power is to try and rig an AC to DC converter with the right voltage/amperage into the battery compartment.
Example: Let's say there is a device (MP3 player as an example) that uses a single AAA battery (1.5V). Is there an AC to DC adapter out there that you know of that has, instead of a regular DC plug on the end, some sort of plastic with metal on the ends looking thing that is the same size as a AAA battery?
Jeff
Answer:
Such things do exist as commercial products. They're not common items, though.
Fortunately, it's not actually very hard to make a dummy battery (or batteries) yourself. You could use wooden dowel for the body and tacks for the end contacts, for instance. Wire the result up to an AC adapter with an appropriate rating, and you're in business. If you want to be able to close the battery door on the gadget you're installing the dummy in, you'll need to cut a slot in it for the wires; this is probably why these things aren't common in the retail market.
RA8 to MP3
I think I've got a "George" - it's boxed as "Teleadapt Mini MP3 Player".
Do you have any experience of getting George to work with RealOne/Real Jukebox? I have a whole stack of RA8 files, and Real don't seem to have a plug-in to convert to MP3 for George to play. Do I have to do it all manually?
Gareth
Answer:
DBPowerAMP will do it (assuming you're
looking for a Windows utility). Free, supports batch operations, and also supports RA8
with an optional codec. Looks
like a good option to me.
You'll lose quality when converting the files, of course, but they ought to be OK for portable player use.
Portable cinema
Any thoughts on whether an outdated laptop with 12" screen could be modified with a DVD drive to become a portable player?
Dave
Answer:
Maybe. It'd need a bit of CPU power to do the DVD decoding - at least a 300MHz Celeron
or P-II, or a somewhat slower K6. You want 400MHz, for comfort. It'd also need a fast
enough interface to the DVD-ROM drive. USB 1.1 should be fine for DVD playback, and
a PCMCIA-card-driven drive would also be OK, though probably not at all cheap. The best
solution would be a DVD-ROM drive that plugged in where the laptop's CD-ROM drive is
now, but if one of those isn't available as a factory option, then you won't be able
to find one.
If the old laptop's screen has a really slow response time, mind you, all of this may be a waste of time; your movies will blur unpleasantly. If it's young enough that it has a fast enough CPU, though, it shouldn't be too awful.
Get it off me! GET IT OFF ME!!
I'd like to buy a set of rare earth magnets, but I've got a little problem.
Last year, I got shot with a BB from a high-powered airgun, and it is lodged in my hand, between the index and middle fingers. Run-of-the-mill magnets stick to it, and most are close enough to it to hang there unaided, but what would a NIB magnet actually do to the piece of brass in my hand? Will this be a humongous problem?
Ben
Answer:
If the BB actually were made of brass, there'd be no problem, but it's steel (probably
copper-plated), so a NIB
magnet will grab it quite hard.
It depends on the size of the magnet, of course. A little half-inch long, eighth-inch-wide rod might hurt; anything smaller probably wouldn't (though I am just guessing).
If you get near to any of the big Serious Pinching Hazard magnets, you'd do well to keep that hand behind your back.
Mystery goop
I just got a new retail box P4/Celeron processor, and stuck on the bottom of the heatsink was a piece of foil covered in this black stuff that gets all over your fingers - what is it and what is it supposed to do?
I'm now not really sure if I was supposed to peel it off or not - the pictorial instructions didn't show it. I can't get it back on anyway. Do I need to clean the remaining bits of black stuff off the bottom of the heatsink before I install it? And what about putting some thermal goop on?
Simon
Answer:
The black stuff is a standard single-use thermal transfer pad, not unlike
this stuff. Ordinary heat sink grease will probably work
a bit better than it, so cleaning the black square off and replacing it with some grease
is fine. For practically all purposes, though - and definitely for your P4-Celeron -
the standard stuff is more than good enough.
Flat-panel alternative?
A quick question related to the ongoing LCD discussion: do you think that the arrival of consumer grade bio-luminescent displays (not sure what the proper term is) in the next few years will tip the scales in favor of flat panels?
I understand that DuPont is in the process of creating some small screens for devices like MP3 players, but it's only a matter of time before this technology can be used for desktop displays. My understanding means that this would (eventually) allow for cheaper, higher-resolution displays with a CRT-esque contrast ratio, since no cold-cathode backlight would be needed. I'm having trouble coming up with more information on the subject, so I thought perhaps you could enlighten us.
James
Answer:
If they can get a decent lifespan out of the things, then yes, but so far Organic LED
displays (OLEDs, which are what I think you're talking about) don't live long enough
to be useful as all-day monitors. The usually quoted lifespan for OLEDs at the moment
is 10,000 hours, though I don't know whether anybody's making screens that last that
long yet. 10,000 hours is four and a half years, if the screen's only on for six hours
a day, but it needs to be higher. CRTs and LCDs and plasma screens all wear out as well,
and if OLED screens only last (say) three years but are really cheap then they'll sell,
but they're not quite ready for prime time yet.
The OLED screens that've shown up on phones and such have, I think, much shorter lifespans, but that's OK because they're only likely to be used for a few minutes per day, and the early adopters who buy them will be buying another phone in a year anyway.
Here's an article on the subject; here's a primer and link-source that doesn't mention the lifespan issue.
Idling Athlon
How far would you have to underclock a new Athlon to be able to cool it passively? Imagine that the case has a fanless PSU, little space, and few airholes. I want to know how it compares in performance to the fastest fanless C3.
Bennett
Answer:
I don't think this would work.
At full Thermal Design Power, a Palomino Athlon XP at stock voltage is good for 22 or 23 megahertz per watt. Thoroughbreds and Bartons will do about 30MHz/W. Real power consumption will be less than that almost all of the time, but you'd better design for full TDP if you know what's good for you.
Now, dropping the supply voltage as you drop the core speed will be possible and will help, but you're still not likely to see better than 40MHz/W at full CPU utilisation, and it may well be considerably worse than you'd expect; the power-versus-speed graph is likely to smooth out at low speeds.
Even in a case with a PSU fan, you're not going to be able to cool more than about a 15 watt CPU (a Thoroughbred at 500MHz might manage that, but I wouldn't be surprised if it didn't) with any heat sink that'll fit on the board. With a fanless PSU and little ventilation, five watts might be pushing it. I don't think you can clock a current Athlon that low.
Further free lunches
Check out the stuff on this guy's page.
Not only does he show his testing equipment in his pictures, but he also documents stuff very well, including showing off cams to verify that nothing is Photoshopped.
I'm a pretty hardcore skeptic about overly complex devices claiming to provide free energy, but the MEG he has on the site looks simple enough that it might actually do something interesting, maybe even what he claims. Although his association with Tom Bearden (if that guy isn't a total loony, I'm scared) makes me really wonder.
If you ever get adventurous, I'd love to see a skeptic build one. I'd do it myself if I had the time and the money (though the parts seem relatively inexpensive), but I wouldn't know how to verify if the device worked or not when I was done!
I had another friend of mine who was a physics geek take a look at it, and he basically told me it was impossible, but couldn't explain why. I suggested he build one and see why it didn't work, but he didn't bother because he was so sure it couldn't work despite his lack of solid reasons.
As a side note, what was up with Tesla? Why does every scheme for coming up with these sorts of devices always lead back to him somehow?
Bob
Answer:
Well, there's certainly quite a lot of content in the
JLN Labs site, including considerable cold fusion
enthusiasm. To my knowledge, there really hasn't been any repeatable success in any
cold fusion ideas so far. I'm not qualified to say whether this guy's particular results
hold water (no pun intended); measuring supposed over-unity results based on the amount
of water you manage to blast into the air when you fire an arc through an electrolyte
solution, though, strikes me as being an easily misinterpreted measurement strategy.
Much low-signal-to-noise-ratio discussion of this stuff has taken place on
sci.physics, et cetera.
The guy's keen on "lifters", as well; see here for my opinion about those.
The evidence that the Bearden machine does anything would appear to be based on an AC measurement error, and the theory behind it doesn't make a lot of sense. So if I'm going to construct a weird device, I think I'll opt for one that works. Like a ballrace motor!
As a something-for-nothing machine (oh, sorry, it slowly consumes its magnets, or something, so it's only something for functionally nothing...), the MEG has a very bad pedigree. Something-for-nothing machines are like end of the world predictions; so very many have failed, and none have succeeded, and you're only going to be on this planet for a limited amount of time, so it's not unreasonable to leave investigation of this singularly unproductive field very low on your to-do list.
Nikola Tesla was very clever, and also quite mad. He was, therefore, pretty much "the crank's crank" - a loony who nonetheless unquestionably achieved a great deal. Like a lot of other unhinged geniuses, though, he also had great enthusiasm for some ideas that didn't pan out, a notable example of which was broadcast power - using the earth and atmosphere as a transmission system for electricity.
Broadcast power just doesn't work. You can transmit data through the air, sure, and even useful power if you use a non-broadcast microwave beam or (for the mad-scientist demographic) a great big electric arc. But non-aimed broadcast power, as Tesla imagined it, is a non-starter.
The water is further muddied by people who take Tesla designs that are good for some things - like the "Tesla turbine", for instance - and get it into their head that these designs must be good for everything.
The Tesla disc pump/turbine is real, and little-known, and seldom used, so there's a big mythos about it among people who don't understand the physics involved. It's not amazingly efficient or especially useful for most applications, but they think it must be, 'cos it's been "Suppressed".
While we're on the subject...
My buddy works at a farm, and one time he was assembling an irrigation system under some high tension power lines; you know, the kind that buzz and crackle ominously. He was moving a length of pipe and received a minor (but somewhat painful, he reports) shock where the metal of the pipe touched his bare neck.
Which got me thinking: could a person set up some kind of antenna system under some power lines and (using assorted transformers/inverters/whatever) leech usable electricity from the EMF put out by the high voltage wires? And if possible, would this power be stolen or gleaned (using what would otherwise be wasted)?
Juanito
Answer:
Yes, it'd be possible to make a great big inefficient transformer out of some high tension
lines and a clothes-line-sized coil underneath it, and you could power a light bulb
or a transistor radio or something from it. The idea of getting power from the air,
as mentioned above, is not a new one; crystal radios do it with nothing but the flea-power
energy of the broadcast radio waves themselves.
If you wanted to get a worthwhile amount of power from such a contraption, though, your secondary coil would have to be truly gigantic and/or built around the power wires way up in the air. And the power would not be coming from nowhere; turning part of the distribution network into the primary of a transformer good for significant power would cause a rise in the load on that portion of the grid. You wouldn't just be intercepting power that'd be lost anyway.
A large enough load rise would be noticed by the power company, and they'd probably notice your yard-full-o-wire (or two miles of barbed wire fence suspiciously insulated from the ground by old tyres...) anyway, on one of their regular surveys of the lines. Then you could be had up for tampering with the grid, stealing power or whatever. You could try to fight it in court on the grounds that you didn't touch nothing, Officer, but I wouldn't like your chances.
I remember hearing about a similar situation, when some geek noticed that the local cable TV wire wasn't as well shielded as it should have been, so a coil wound around it - but not touching it - could be used to steal cable.
A coil the size of an umbrella set up under high tension wires would probably yield enough power to run, say, a little microcontroller-powered weather station, or something, without noticeably loading the grid. A rather smaller solar panel and battery would be likely to do the job better, though.
