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The word "How?" springs to mind at this point.
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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.
Why this isn't as simple as it seems - scroll down to II) Hack FAQ [BunsenHoneydew, Oct 16 2005]
The software solution [ixnaum] mentioned [BunsenHoneydew, Oct 16 2005]
Zoomed Video FAQ
whence the quoted quote [BunsenHoneydew, Jan 29 2006]
"...even when your Powerbook has crashed."
whence the other quote [BunsenHoneydew, Jan 29 2006]
A Zoomed video card
Discontinued [BunsenHoneydew, Jan 29 2006]
US patent 8134564
cites this idea as prior art [xaviergisz, Jun 03 2012]
||Isn't the laptop LCD a computer monitor already?
||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.
||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.
||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.
||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... [+]
||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
||But apart from that, cool idea.
Pity it can't really be done the
way you envision it.
||//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], the idea is for an extra *input*, not an output. I haven't seen one yet, although VGA, DVI and video outputs are common.
||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.
||Yeees... you'll still need the matrix driver boards, but I suppose it would make it a little simpler.
||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.
||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
and industrial/ embedded
computers is LVDS. Even that
isn't all that standardised -
pinouts, sync rates and voltages
can vary in
ways. Not to mention the
thousands of LCDs that don't
even standardise to LVDS.
||Read the whole FAQ entry for
||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
"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
||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
||Now, if you could physically tap
into the GPU...
||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
||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 ... "
||"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,
||Include a port to put the monitor on a TV, would help the sight-impared.
||would be quite usefull for digital cameras which have a/v out