Atomic I/O letters column #147
Originally published 2013, in PC & Tech Authority(in which Atomic magazine is now a section)
Reprinted here January 19, 2014 Last modified 16-Jan-2015.
Terry Gilliam computing
Now that there are monitors on laptops that have the same four megapixel resolution as 30-inch desktop screens, could you get the same effect by putting a magnifier in front of one of the smaller screens? If we can fit HD displays into an Oculus Rift, shouldn't we be able to make a desktop monitor that uses one of those laptop panels?
Luke
I'm seeing this movie in a whole new way.
(Hey, I've invented my own split-dioptre lens!)
Answer:
You definitely could put one of the super-high-density
laptop panels
(the ones Apple calls "Retina")
in a desktop monitor casing, but people sit far enough away from desktop monitors
that most of the extra resolution would be wasted. (Ages ago, here,
I wrote about calculating the maximum resolution that's detectable from a given viewing
distance.)
I think this is why nobody seems to make such a monitor. And, unfortunately, sticking magnifiers in front is not going to come near solving that problem.
There are, for a start, severe viewing-angle problems if you stick a magnifier in front of a whole screen. Even if your screen panel has a very wide viewing angle - as all but the cheapest today usually do - there's no way to make a simple lens that'll make it look "the same, but bigger". Looking through the lens at an angle will always be a problem.
Make a lens with varying focal length all the way across it and you could get closer to achieving this, but it'd still be intensely sensitive to the location of the viewer's eyes. Actually, it might not even be practical to make such a contraption that you could view with both eyes at once, when the panel you're viewing only has a seventeen-inch diagonal.
A projection system with a concave screen would work much better, but the closest you can get to that in consumer hardware is multiple monitors in a highly polygonal curved array. (As I write this in early 2014, consumer-market curved screens may not be very far away, but they can be expected to be at the very Bugatti-Veyrons-and-Riva-speedboats top of the consumer market, and aren't necessarily all that exciting anyway.)
It is, however, possible to make screens - and everything else close to you - seem bigger, by simply attaching lenses to your head. This is exactly what commonplace non-prescription reading glasses do.
Anybody who doesn't normally wear corrective lenses can try this out with a sub-$5 pair of eBay reading glasses. 1.0-dioptre will do the job, 2.0 is more dramatic but less practical, higher dioptres may be needed if you're long-sighted in the first place.
Move monitor closer to you, put on reading glasses, observe monitor that now seems bigger and further away.
Three-dioptre glasses for me make it impossible to focus on anything more than about thirty centimetres away, but they're great for working on tiny fiddly objects like circuit boards. And they turn my thirty-inch monitor, still working fine as it approaches its seventh birthday, into an IMAX screen!
(In the olden days there were, and for all I know still are, ads in the back of Popular Mechanics and such for plans and/or gear to make a projection TV, which actually involved just putting a lens in front of a normal TV screen so it would project a large, but very dim, image onto a wall. You could goose up the CRT's brightness beyond what the normal controls allowed by fiddling with the circuitry inside, but the image would still be quite miserably dim, and the brighter you made the CRT, the shorter its life became. You can do the same thing today with an LCD monitor, and it'll work better because the maximum beightness of almost all LCD screens is very, very, painfully, high, but it still won't work especially well.)
Cable pain the first
The sockets on the back of my monitor face downwards, and there's a lip around them, so the only way to see them is by lying on your back under the desk facing up or by putting the monitor flat on the desk.
I kind of understand why this is, the facing-downwards part anyway, because that stops the cables being squashed if you push the monitor up against the wall. But now that I think about it, it occurs to me that about one computer socket in ten is actually readily accessible and easy to plug things into.
How do people who work on computers all the time deal with this without going crazy?
T.
Answer:
There are indeed practical reasons why most computer sockets are where they are and
face the way they face, but this is, as you say, also frequently highly annoying. Identical
non-interchangeable sockets right next to each other (monitor outputs, audio jacks,
the old PS/2 sockets...), sockets
that always seem to require at least three
attempts to get the plug the right way around, and so on and so forth.
Whenever possible you should of course yank the computer in question out from wherever it is so you can actually see what you're doing, but when that's not possible, here are some hints:
* A dental inspection mirror is not tremendously helpful, but it's better than nothing and very cheap.
* A little pen-shaped camera, or optic-fibre inspection scope or "snake camera" with its own little screen, is much better than a mirror. And also complete overkill. But don't let that stop you using this as an excuse to buy one!
(Low-end skinny cameras and low-resolution borescopes can actually be had quite cheaply these days, which moves these things into the same "may come in handy, doesn't cost much" category as the reading glasses.)
* If you can get your finger or thumb onto an unknown invisible connector, press said digit firmly onto it, then inspect the dent it left in your flesh. Plug orientation... revealed!
* Got a smartphone with a front-facing camera? Poke the phone in there such that it can see the mystery connectors, and you can see its screen. Or just record some video.
* Got a digital camera or phone with built-in panorama features? Click several pictures of the back of whatever device is giving you grief, and stitch 'em together into a geometrically untidy but highly informative result!
(You can also do this with photos from any camera and Photoshop, or various other imaging software. That's ridiculous if you're only trying to figure out which way up the video socket on the back of a computer is, but if you're dealing with a monster home theatre amp or scientific equipment or something, it could be justified.)
Cable pain the second
I just plugged a USB cable into the back of my PC.
What I plugged it INTO, though, was not a USB socket, it was a network socket.
My computer had a motherboard Ethernet socket. A bit of investigation revealed that after plugging this USB cable into it, the physical socket still exists, but not that network... card, or whatever you call it when it's not a card but built into the board.
I was connected to the actual network via a USB Wi-Fi dongle, and that still works, but I'm going to need to buy an actual network card if I ever want to connect to a wired network again.
My question for you isn't "how can I magically fix this fried motherboard network thing", but "why in the hell is it possible to plug a USB cable (invented 1996, according to Wikipedia) into a network cable socket (invented 1990, ibid.), and blow the damn network thing up?!"
Isaac
Answer:
I don't know either.
Six megacorps contributed to the original USB standard, though, so I'm currently visualising a large room full of engineers all pointing fingers of blame at someone else.
However it happened, USB Type A plugs are a snug fit in an "RJ45" Ethernet socket, but yes, they do fit. And if you push them in far enough they short all of the Ethernet pins together.
The effect this will have is variable.
If everything's turned off and you don't really mash the plug in there, there should be no electrical or physical damage to anything.
If it's an ordinary 10BaseT/100BaseT/Gigabit-Ethernet device that's powered up, shorting its pins may or may not kill it, probably without much drama.
If it's a Power-Over-Ethernet socket, though, it is entirely possible that there will be excitement up to and including actual flames.
In all of these cases a USB device on the other end of the cable should be fine, since it's just the beefy rectangular shield portion of the USB A connector that's shorting the pins. Even if there's fire and flame, it probably won't even mutilate the USB plug.
(Oh, and the generic term for a network adapter whether it's a standalone object or built into something else is just "network adapter". Or Network Interface Controller, "NIC", if you're fancy.)
Didn't even need any fence wire
The plugpack for my ADSL/Wi-Fi/router thing went pop earlier today, but I noticed it was a 12-volt, 1-amp power supply, barrel outside negative and barrel inside positive. I fossicked through my drawer of old phone chargers and other crap and found a power supply matching the electrical specs and with a barrel plug almost the right size.
The replacement plugged in but didn't make contact properly - the hole in the middle is too big. So I threw sanity to the wind and just crumpled up a little bit of aluminium foil and stuffed it in there with a toothpick. Seems to work fine now, if this email gets to you anyway!
So I suppose this is another one of those letters asking "will my brilliant idea burn my house down tonight, or will it wait a week or two"?
Helen
Answer:
This is the sort of thing that brings to mind "if
it's stupid but it works, it's not stupid". I'm racking my brain to think of reasons
why this could go wrong, but I really can't think of any way in which poking foil into
the inside of a normal two-contact barrel plug could cause a serious problem.
It could perhaps get compacted and stop making contact until you put more foil in there. Or a bit of spring from a ballpoint pen... whole new vistas of ill-advised power-plug modification are opening up for me, here.
The worst I can really see it doing, though, is coming back out enough that it shorts the plug and you need to find yet another plugpack.
The proper way to replace a plugpack is of course to choose one with the right electrical specs and connector, or replace the connector with one that fits the device properly.
The only further concern is to make sure you're using a regulated plugpack, which will output roughly the same voltage no matter how heavily loaded it is, up to its current-output limit. Old-fashioned heavyweight plugpacks (which are chiefly composed of iron-cored transformer) often aren't regulated, and can deliver a dangerously high voltage - up to root-two times the rating - into a light load.
(If a plugpack's regulated, by the way, then it doesn't matter if its current rating is higher than the one it's replacing.)
Some old plugpacks may even give AC output - for some reason, plugpacks for phone-line modems were often AC. But virtually all modern plugpacks are lightweight regulated DC world-compatible switchmode types, and almost always the right polarity, too. Almost anything with a barrel plug will be outside-negative, inside-positive.
All that said, though, you can't argue with success.
(Correspondence is requested from any readers who are more imaginative than me about how this bodge job will result in Helen's fiery death.)
