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Laptop monitor input

For use with other computers
  (+28, -1)(+28, -1)(+28, -1)
(+28, -1)
  [vote for,

Make the external monitor connection on a laptop bi-directional, allowing the laptop LCD to be used as a standard computer monitor.

A small button allows the user to switch between internal and external signal sources. A low powered microcontroller allows the display to be used when the rest of the laptop is powered off.

Aside from being a nifty portable display, it allows otherwise dead laptops to retain visual functionality for use with other computer systems.

Aq_Bi, Oct 16 2005

Applefritter FAQ http://www.applefritter.com/faq
Why this isn't as simple as it seems - scroll down to II) Hack FAQ [BunsenHoneydew, Oct 16 2005]

VNC http://en.wikipedia.org/wiki/VNC
The software solution [ixnaum] mentioned [BunsenHoneydew, Oct 16 2005]

Zoomed Video FAQ http://www.winbookc...te/WBTA00210757.htm
whence the quoted quote [BunsenHoneydew, Jan 29 2006]

"...even when your Powerbook has crashed." http://www.insanely...eatures/010823.html
whence the other quote [BunsenHoneydew, Jan 29 2006]

A Zoomed video card http://www.psism.com/vc.htm
Discontinued [BunsenHoneydew, Jan 29 2006]

US patent 8134564 http://www.google.c...v=onepage&q&f=false
cites this idea as prior art [xaviergisz, Jun 03 2012]


       Isn't the laptop LCD a computer monitor already?
jellydoughnut, Oct 16 2005

       Damn, I thought of this idea on the 10th of October. Then I forgot, and now, on the 15th, you posted it! Good idea though, and +bun.
-----, Oct 16 2005

       I really like this idea. For notebooks that don't have this featuere yet, I believe there is a fully baked solution that involves using special software that let's you use your notebook's monitor as a second or third desktop monitor by sending the image over ethernet. I saw it somewhere once but didn't bother trying it because it looked like too much trouble ... but a built in switch as you describe would be awsome.
ixnaum, Oct 16 2005

       The problem with the software solution is the limitations of the ethernet. Even at 1Gb/s, it still doesn't come close to the bandwidth needed for high resolution full motion video.
Aq_Bi, Oct 16 2005

       I thought of this last time I needed it, but strangely enough it never occurred to me to post it on the hb. I wonder how many other ideas have slipped through... [+]
wagster, Oct 16 2005

       Quoting from the Applefritter Hack FAQ - see [link]   

       "Laptop displays simply don't speak the same language as CRT monitors, electrically speaking. It requires a complex wad of electronics to turn output meant for a CRT into input suitable for an LCD, and that wad of electronics is referred to as the 'controller'. You won't find a controller you can salvage in your laptop anywhere, because it 'speaks LCD' directly, and thus doesn't need one."   

       Note for "CRT" above you can also substitute "desktop LCD monitor". The protocols are the same.   

       But apart from that, cool idea. Pity it can't really be done the way you envision it.
BunsenHoneydew, Oct 16 2005

       //It requires a complex wad of electronics to turn output meant for a CRT into input suitable for an LCD//   

       Most new desktops come with digital output option for LCD monitors. Analog (CRT) is quickly becoming obsolete. Going digital - digital should be a matter of 1 tiny chip or a slight modification on the existing graphic chip.
ixnaum, Oct 16 2005

       [ixnaum], the idea is for an extra *input*, not an output. I haven't seen one yet, although VGA, DVI and video outputs are common.
wagster, Oct 16 2005

       What [ixnaum] means is converting an external DVI signal to the laptop's native display involves much less circuitry than converting from analog VGA. Although this does somewhat limit its versatility.
Aq_Bi, Oct 16 2005

       Yeees... you'll still need the matrix driver boards, but I suppose it would make it a little simpler.
wagster, Oct 16 2005

       This is a very good idea. I once thought of this possibility myself. I have a portable case for my desktop PC that I use for lan parties and doing live video presentations. There isnt a laptop on the market that is powerful enough to keep up with my desktop PC so I end up having to lug it around. Rather than having to find a place to set up a montor, keyboard, and mouse, it would be nice to open the laptop, even if I had to remove the guts, so that I could just use the keyboard and monitor part more convieniently.
Jscotty, Oct 17 2005

       No, really. This isn't just "one tiny chip" or a 10 cent add on at manufacturing. The "digital output option" you're thinking of is DVI. The one commonly used in laptops and industrial/ embedded computers is LVDS. Even that isn't all that standardised - pinouts, sync rates and voltages can vary in drastic, display-and- computer-destroying ways. Not to mention the thousands of LCDs that don't even standardise to LVDS.   

       Read the whole FAQ entry for more details.   

       VGA to LCD converter boards exist, but they are large, complex, and start at around $200. Each one only supports a few LCD panels, because of the aforementioned non-standardised LVDS "standard", and so they are short-run manufactured items with no real economies of scale.   

       I imagine DVI to LVDS boards would be similar, minus the A/D stage. Then there's the physical switching of the LCD from one controller to the other.   

       Remote display (and control) is built in under most unix-like OSes. The local GPU/CPU does the grunt work of drawing images, all the remote has to send is basic information on what goes where. If I remember this right, VNC works somewhat similarly.   

       Now, if you could physically tap into the GPU...
BunsenHoneydew, Jan 28 2006

       Okay so it turns out something similar to this has been implemented on Mac (and some PC) laptops since late last century. It's called "zoomed video" - it's PAL/NTSC video input direct to the host GPU.   

       Quote from the linked site:   

       "ZV Port allows video data on a PC Card to be transferred directly into the VGA frame buffer.   

       What Is the ZV Port?   

       The ZV Port is a point to point uni-directional video bus between a PC Card host adapter and a VGA controller. The ZV port ... allow[s] NTSC decoders to deliver real-time digital video straight into the VGA frame buffer from a PC Card ... "   

       And elsewhere:   

       "Zoomed video takes an image from another source (analog video camera, S-video device, VCR) and displays the picture on your PowerBook screen. At full resolution ... Independent of the CPU, zoomed video means you can still watch TV even if your PowerBook has crashed."   

       So there you go. Seems as long as your lappie has the right type of Cardbus slot, and your other computer has a TV out card, you're set.   

       I'm removing my [-].
BunsenHoneydew, Jan 29 2006

       Include a port to put the monitor on a TV, would help the sight-impared.
krigre55, Nov 30 2007

       would be quite usefull for digital cameras which have a/v out
kamathln, Jul 04 2010


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