Making a Privacy Monitor From an Old LCD 185
ryzvonusef writes "Instructables Member 'Dimovi' utilized a spare LCD monitor and converted it into a 'privacy' monitor. He took apart the monitor's plastic frame, cutting out the polarized film with a utility knife and removed the film adhesive from the glass panel before reassembling the monitor, which now shines a bright white regardless of what is actually being displayed on the screen. He then removed the lenses from a pair of theater 3D glasses, and replaced it with the polarized film he had just removed from the monitor. Now, he is the only one who can see what he is doing on his computer."
Great hack. (Score:5, Interesting)
Very interesting hack. It would be perfect for laptops that are used while travelling (watching pr0n during your flight?).
I wonder how easy or difficult it would be to hack a notebook screen.
lol, captcha: decency
Re:Great hack. (Score:5, Funny)
A notebook screen should be fundamentally the same.
As for the idea of watching porn during an airplane flight... the image on the screen is only the beginning of why doing that is frowned upon.
Re:Great hack. (Score:4, Funny)
Earphones have already solved the audio side of the problem.
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Earphones don't solve the problem either.
Here's a clue: Why do men like to view porn movies? And what do they usually do while watching them?
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As for the idea of watching porn during an airplane flight... the image on the screen is only the beginning of why doing that is frowned upon.
Earphones have already solved the audio side of the problem.
Joke I know, but does *anyone* seriously watch porn with the sound turned up anyway?
99% of it is unbearably badly dubbed (and cheesy, and unconvincing) crap that totally ruins the illusion. Urgh.
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Which laws do apply during flight depends...on many things, but the general rule is that while in flight the laws of the country of registration of the plane apply. For commercial flight not registered in the same country as the commercial operator of the flight, the operator country's laws do apply. This matters for what happens between the passengers inside the plane.
The above statement is, obviously, overly simplified, since many things can complicate matters. For example the flight could be leased in a
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entirely depends on the originating state of the airline. You obey that country's laws.
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You will discover the qualities of porn audio when you move out of your mothers basement. Either that, or buy a pair of headphones and a lock.
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You *do* know that a lot of sunglasses contain polarisers, so your neighbour on the plane might get the action as well? Observe what happens with some monitors viewed through sunglasses when you've got the monitor in portrait, others seem to have it twisted 45degrees so as not to black it out whichever way it is.
Re:Great hack. (Score:5, Funny)
But wouldn't anyone with a pair of polarizing sunglasses be able to see your screen?
I don't know enough about such things to know. I lent out my copy of Newton's Optics, and I keep my polarized sunglasses in a secret compartment I cut into the Enumeration of Lines of the Third Order.
Anyway, leave me alone. I'm trying to kill Al Ghul and bang Talia without having to squat in the Lazarus Pit.
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Yes, although they might have to tilt their head to get the polarization of their sunglasses oriented correctly in relation to the polarization of the screen.
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Re:Great hack. (Score:4, Insightful)
I'd be willing to bet that the minute someone on an airplane sees you staring at an all white screen for any period of time there will be an Air Marshal tapping you on the shoulder.
Re:Great hack. (Score:5, Funny)
At which point you go "National Security. If you had the security clearance, you'd have the glasses to see past the security layer. Good day, sir."
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It would be perfect for laptops that are used while travelling (watching pr0n during your flight?).
Flight attendant to other flight attendant: "The in-flight movie isn't in 3D. I wonder why all these passengers have 3D glasses on..."
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Very interesting hack. It would be perfect for laptops that are used while travelling (watching pr0n during your flight?).
Funny you should mention that given this story [cnn.com] was published in CNN today! There might be a market for these things.
Re:Great hack. (Score:5, Interesting)
Not that hard... I've done it several times (the dis-assembly/re-assembly part... not the screen hack)
It helps significantly if you have the assembly manual but not required.
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It helps significantly if you have the assembly manual but not required.
I won't disassemble or reassemble any laptop that wasn't my own, for love nor money, unless I've got a manual... which pretty much limits that to Dell machines (LOVE their documentation online) or Apple computers (due solely to the existence of iFixit), but that's just IME, of course.
Granted, when I first attempted tearing apart and repairing laptops (It's a computer, how hard could it be!), I either was unable to fix them, or ended up making the problem worse, or ended up with "extra" screws, or whatever.
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Now you can find lots of online videos of people dis-assembling smartphones and laptops.
Youtube, it's for more than just stupid kitten videos now.
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Pal, I do maintenance. Big stuff, small stuff, and everything in between. Electronics, hydraulics, electrical, heating, cooling, servo motors - you name it. If we take something apart, and put it back together, and we DO NOT HAVE any left over parts, we know that we've screwed up.
Once in awhile, we have to open the patient back up, to put one or more of those spare parts where it belongs, but that doesn't happen very often.
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You could get the maintenance manual for Sony Vaio laptops. So far, I've replaced the screen, the keyboard, the folding screen LCD-switch-latch circuit board, the hard disk drive (upgrades), memory (upgrade), CPU cooling fan assembly.
Just about every computer repair shop wouldn't go as far as trying to replace a screen.
Re:Great hack. (Score:5, Interesting)
Umm... have you actually disassembled an Laptops LCD screen?
after taking the actual display out of the case, don't be fooled by thinking that thin == simple.
There are about 7 separate paged layers sandwiched into metal bezel... not actually hard to deal with, but if you dislodge one, you can destroy your screen (all the electronic connections are from 1 edge of the screen - the top, when I did it).
Putting it back together was a bit difficult... the backlight shines up through the screen, and it took me a dozen tries to get it to the point where the screen was usable.
It was a very fiddly job overall.... especially when in the end it was so easy to resolder the CCL that was attached to the bezel (I didn't need to dissassemble the display at all)...
Mind you, the laptop in question is the better part of 10 years old, so you have an easier time of it.
good luck...
the down side (Score:5, Funny)
Cool and clever hack. But it assumes that what you're displaying on the screen is more embarrassing than being seen wearing 3D glasses. An easier solution would be to just never let anyone into your lair.
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Cool and clever hack. But it assumes that what you're displaying on the screen is more embarrassing than being seen wearing 3D glasses. An easier solution would be to just never let anyone into your lair.But then you'd have to hoover the Cheeto crumbs from under your Command Throne yourself.
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yah, but a what cost? They weren't Rose coloured-glasses
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But were they Rose-scented glasses? This is important!
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Smell my finger.
I wish.
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Nope, any proper polarized glasses would work here. For example, polarized sun glasses.
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You can put the film on any pair of shades. All it requires is a linearly polarized filter. Unfortunately, you'll find a wide selection of sunglasses with linearly polazized lenses (advertised as reducing reflections) at your local gas station. Although, they might be 90 degrees off.
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Because polarization involves filtering out all of the light except the waves of a certain angle, they will inevitably look darker than Plain Old Glasses.
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Only one who can see the screen? (Score:5, Insightful)
Sure, unless anyone else is wearing polarized sunglasses in the vicinity.
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Sure, unless anyone else is wearing polarized sunglasses in the vicinity.
Yup. What you need is to hack one of the 3D systems that uses active LCD shutter glasses.
The screen would rapidly alternate between showing the actual image and a screen full of dazzling random hash. The shutter glasses, synced to the monitor would block out the hash and allow the user to see the image. Use a sync cable rather than some optical system, let the frequency wander randomly a bit and include some rogue flickering with the hash to make it hard for a bystander with active glasses to get in sync
Which is why it's not going to work on me. (Score:2)
Yeah, the minute somebody next to me starts using a device that blasts white light into my face, I'm going to put on my polarized sunglasses, which are always in my right inside jacket pocket.
I wouldn't even be trying to defeat his privacy hack, I'm just very light sensitive so I always carry shades.
Oh, look - pr0n!
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Turn them 90 degrees. Bam! Vertically polarized.
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Turn them 90 degrees. Bam! Vertically polarized.
Ouch, my neck!
And, besides, that won't work if using circular polarization (which is what allows 3D movies to work even if a person tilts his head to the side).
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what about circular polarization?
Then any joker with a pair of 2D Glasses [2d-glasses.com] (or someone with regular 3D glasses and one eye closed) could read them :-)
Seriously though - the hack relies on the fact that LCD displays use linearly polarized light internally.
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If you're wearing a pair of polarized sunglasses, it's always good for a couple seconds of entertainment to sit there and look like an idiot tilting your head back and forth watching an LCD screen flip back and forth between normal and all black as the polarization lines up / goes perpendicular to the monitor's.
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Done Before (Score:5, Funny)
Immediately thought of This. [stanford.edu]
but but (Score:5, Funny)
When you don't want anyone seeing what is on the screen aren't you usually naked? Glasses aren't going to hide much, IMHO.
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So there I was, sitting at my computer and watching porn. Naked, of course. All of a sudden, my boss walked into my cubicle!
Boss: What are you doing?
Me: Working on a spreadsheet.
Boss: Great! Keep up the good work.
Whew! Saved by the privacy monitor!
One problem... (Score:2)
"Ok, time to get some work done on my computer. Where'd I put those glasses?!!!"
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Some people already have to ask that question.
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Geez, that scenario happens to me many times a day already...
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Wasn't that a Twilight Zone [imdb.com]?
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It was the episode with the actor that played the Riddler on the 50's Superman tv show.
Useful, but not very private (Score:5, Interesting)
I think the first description of such a system was in a golden age science fiction story. Car head lights were polarized diagonally. You'd wear glasses that allowed your light to be bright, but oncoming ca's headlights would be reduced. Of course unsuspecting pedestrians would be blinded.
Re:Useful, but not very private (Score:5, Informative)
Why not just buy a 3M privacy filter? (Score:3, Informative)
Recycling is cool and all, but it's not like this is a new / unique / unanticipated capability:
http://solutions.3m.com/wps/portal/3M/en_US/SDP/Privacy_Filters/ [3m.com]
William
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This glasses-based solution seems much more effective, especially for those who already wear glasses. Adding a polarised coating would cost pennies.
Neat... (Score:2)
He'll need a tin foil hat too.... (Score:2)
Inefficient. (Score:2)
Inefficient. Rather than making it harder to look at the screen, make viewers not want to look at the screen to begin with. Make the background image goatse. Also provides an interesting location to place the stereotypical "GUI trash can".
Just a bit too late (Score:2)
Not impressed. (Score:4, Funny)
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http://www.geowall.org/ [geowall.org]
Designed for different images for each eye, but you could easily do it your way.
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Um, yeah... (Score:2)
Why do I have to see his screen to know what he's doing in his computer? in fact, why do I have to be on the same continent?
Er....? (Score:3)
Didn't we just spend the last 20 years designing laptop/lcd flatscreens so that they didn't have the damn single-point-of-viewing issue? I seem to recall the original, dim LCD screens being an enormous pain in the butt because if you moved your head about 3" to either side, you couldn't see anything.
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Impossible: the graphic card can not have any control over the polarization of light emitted by the screen.
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With a 3d monitor, it could be interesting to try. For 1 'eye', output the normal image. For the other, output exactly the opposite image. For normal vision, it would look like a solid image, but wearing 1 half of the 3D Glasses should give you the normal image.
I think I'll try this later, with the standard 3D image viewer app.
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surely a graphics programmer could coax an Nvidia/Ati card to give the same effect ?
It's been done. See an example here [teamworkphoto.com]
Yes, it is what you're expecting.
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Do you understand what "polarization" is? As a phenomenon of physics, it falls pretty firmly in the "hardware" field.
Re:Sunglasses (Score:5, Interesting)
Hell, I might even suggest this for my own workstation (back to the door, frequently working on sensitive data). I wear glasses anyway; It wouldn't be difficult to fit the film to the lenses I already require.
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Hell, I might even suggest this for my own "work"station (back to the door, and I hate it when the boss sneaks in from behind).
FTFY
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"For someone who works with sensitive information, yet is in a publicly accessible area, this is a genuinely great idea"
no it's not. if you are working with sensitive info in a public area then you are being very, very, VERY stupid. at LEAST work against a wall where it is impossible for someone to walk up from behind.
It's why the SQL guy at most corporations get's an office or a corner cube that has a single path in and no way for someone to look over his shoulder.
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Speak not their names lightly.
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I think if someone wants your sensitive information, they will bear the social stigma attached to wearing sunglasses indoors.
Re:Sunglasses (Score:5, Insightful)
Iirc polarizing sun glasses always have horizontal polarization (or was it vertical, can't remember, it's basically aimed at removing the rays reflected off water surface).
You can require exact opposite polarization here, meaning that sunglasses wouldn't work.
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Just turn your head sideways.
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You and several others who suggested this probably didn't think of two major problems:
1. You're going to be pretty obvious
2. You head weighs a LOT. Neck muscles are designed to keep your head straight and turn it, and tilt it for a few moments, mostly into front or back (i.e. getting view of your surroundings, what's right in front of you and above you). Prolonged attempt at even a modest 45 deg sideways tilt will have your neck muscles scream for mercy in just a couple of minutes unless you're very fit - w
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Good point, but how long will you be able to do that without alerting your victim? They still need to be high enough to be between your eye and the screen, and close enough to your eyes to give you sufficient view of the screen.
As noted, all methods of "privacy screening" are defeated by an offender willing to spend a significant effort to defeat them. That said, this will defeat all CASUAL people taking a peek, including those who are wearing polarized glasses.
Re:Sunglasses (Score:4, Insightful)
I did a quick test at my desk with my polarized sunglasses and two different monitors. Both blocked the light when I tilted my head 45 degrees to the right and it was at full brightness 45 degrees to the left. The image only was completely blocked in a very narrow range.
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I know, I actually exclusively use polarized glasses since I'm something of a swimming enthusiast in the summers (and I learned to hate water reflections), but things like my phone clearly not well visible with glasses on due to polarization issues.
But as I mentioned in another post, try sitting for a while with a 45 degree tilt of your head for more then a few minutes, then report back on just how painful it was for your neck. Not to mention your extreme obviousness to the person you're "spying" on.
And of
Re:Sunglasses (Score:5, Informative)
Sunglasses have horizontal polarization. It's aimed at preserving the light reflected from horizontal surfaces, while filtering half of the light comming directly from the Sun.
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This is false. Sunlight is fully unpolarized, therefore it will not be hindered by polarization until it is polarized by being reflected. To quote wikipedia on the origin of usage of polarization in sunglasses:
Some models have polarized lenses, made of Polaroid polarized plastic sheeting, to reduce glare caused by light reflected from polarizing surfaces such as water (see Brewster's angle for how this works) as well as by polarized diffuse sky radiation (skylight). This can be especially useful when fishin
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Sunlight is fully unpolarized, therefore it will not be hindered by polarization ... polarizing has no effect on brightness of unpolarized light (beyond the impact of filter's imperfect optical properties of course).
You are wrong.
http://en.wikipedia.org/wiki/Polarizer#Malus.27_law_and_other_properties [wikipedia.org]
A beam of unpolarized light can be thought of as containing a uniform mixture of linear polarizations at all possible angles. Since the average value of cos^2 theta is 1/2, the transmission coefficient becomes I / Io = 1/2.
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Beam of unpolarized light != Beam of unpolarized light from the Sun.
Unpolarized light from the sun is very uniform in term of linear polarizations, unless it's reflected from a surface.
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Unpolarized light from the sun is very uniform in term of linear polarizations
And the transmission coefficient of that unpolarized light - a uniform mixture of linear polarizations - is 50%. You practically just quoted the passage from Wikipedia. I'm not sure if that means you didn't read it, or read it and just didn't understand it.
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Actually I quoted from my head, and the last time I studied the subject was a two page lesson from high school physics over a decade ago. I just found the book in question and compared it to your link, and unfortunately it appears to not delve into the intensity issue, which is probably why I was wrong about it.
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In my defense, there were multiple false claims in addition to this correct one in those posts, such as claim that polarizing glasses were used to preserve reflections. But that doesn't excuse the fact that I was indeed wrong on this one. Let this be a lesson to all participants: sometimes one proper link and a short explanation of what part of the link explains the problem with the hypothesis goes much further then a lot of saying "because this is how it is".
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Looks like my definition of unpolarized light is a bit off. Unpolarized light does not just vibrate along one axis, but my point still remains. The filter will block one whole component of the wave as it passes through, but leave the other untouched.
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You are correct that one wavelength will be "stripped" - this is the entire point of the phenomenon we call polarization. Part where your hypothesis falls apart is where you assume that losing one dimension of the wave of light from the Sun reduces the amount of luminance carried by the wave of light from the Sun. This is false.
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Part where your hypothesis falls apart is where you assume that losing one dimension of the wave of light from the Sun reduces the amount of luminance carried by the wave of light from the Sun. This is false.
It's not false. It does, and necessarily so. It's the same reason which allows LCD displays to vary between completely dark and completely light. As the angle between the polarization of the light varies with the angle of the filter, the intensity will be reduced by the cosine of that angle.
If you put two polarizing filters in line (with their polarizations aligned to each other), the second filter will not significantly diminish the intensity of the light passing through the first. However, if you rotate t
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Sunglasses have VERTICAL polarization. It's aimed at blocking horizontally polarized light such as glare from the highway or water.
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I have a pair of those and it makes it tough to watch videos on my phone in landscape mode.
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They will work fine, the image will just be the inverse (black and white swapped).
Re:How long... (Score:5, Informative)
Sony kind of came out with that...the Playstation Display allows for two people to play fullscreen simultaneously.
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3D TVs are only 3D because traditional LCDs don't have a high enough frequency for shutter-lense 3D. You could use an old CRT for 3D just as well. Polarised 3D is only used in cinemas.
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Funny, I have polarized 3d in my basement.
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LG disagrees. [lg.com]
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More like $50 than $5, but yes. And if you are within the narrow viewing angle allowed by the filter, you can still see the screen.