Laptop LCDs as screens almost impossible, still never done?

jjhammerstein · Post by **jjhammerstein** » Sun May 03, 2009 10:05 am

I know that it's supposed to be extremely difficult to run composite or VGA to a laptop LCD.
That said, why hasn't it been done? There are plenty of EEs around, don't you know how? It would be SO awesome, and SO much better than an inch thick screen, plus they're low power. Why why why?

manuba · Post by **manuba** » Sun May 03, 2009 10:44 am

because you need a control board which is controlled by the motherboard so you need the whole computer plus commands to the screen

jjhammerstein · Post by **jjhammerstein** » Sun May 03, 2009 11:48 am

That isn't how it works. The idea is making a new control board that takes other inputs.

Kyo · Post by **Kyo** » Sun May 03, 2009 12:24 pm

Because you would have to make a new control board. First of all, you gotta know what signal exactly the screen takes, and then you gotta do translation magic, which is not always easy, especially from analog to digital.

Dark-Aries · Post by **Dark-Aries** » Sun May 03, 2009 1:10 pm

there are control boards for labtop screens, but to buy the right screen isn't always an easy job. Most if them get taken from the folks at lumenlab. This guys sells them but his stock is not the best. When he finds the screens, he gets quite a few, but they sell out quickly. What we would need is the company that makes the control boards, and the conmpay that makes the screen, Ben buys in bulk or anybody else, then we buy them off of that person.

tom61 · Post by **tom61** » Thu May 07, 2009 10:38 am

jjhammerstein wrote:I know that it's supposed to be extremely difficult to run composite or VGA to a laptop LCD.
That said, why hasn't it been done? There are plenty of EEs around, don't you know how? It would be SO awesome, and SO much better than an inch thick screen, plus they're low power. Why why why?

To be done easily, the implementation would have to be specific to that LCD, and likely only support the native res of that LCD as scaling is a pain to do properly. Then there are the issues of most LCDs having extremely difficult to find connectors, and inverters are likely only on the laptop's motherboard and would have to be rebuilt. Even then, it'd be difficult to have the parts cost of the controller be less than a controller off ebay (there used to be a Chinese seller with a controller that took Composite, Component and VGA and would make the cable needed for around $100 shipped)

GhaleonX · Post by **GhaleonX** » Mon May 11, 2009 7:49 pm

I tried getting a few different screens to work for an xbox 360 a while back (as the 360 can output several different signal types, it was an ideal device to try some screens with, imo). I had a couple of portable dvd players I hacked apart, both of which came with a control board which interfaces between the dvd board, and the screen. While at least one of the DVD players had a composite in, you cannot (at least, I couldn't find with an o-scope) input that type of connection directly to the board.

I only tried one laptop (dead mobo, but screen should've been 100% fine), and it seemed to have the same situation (control board to interface between the two), and couldn't get a signal to output to any of the aforementioned screens. I've taken this to mean that the input signals (let's say composite video) are accepted and converted before they get to the control board (so the control board is receiving a proprietary digital signal; not just the screen).

Hope that helped explain the 'why' a bit.

jjhammerstein · Post by **jjhammerstein** » Mon May 11, 2009 8:18 pm

I know why it's hard, but I know it's doable to build a converter.

tom61 · Post by **tom61** » Wed May 13, 2009 3:32 pm

jjhammerstein wrote:I know why it's hard, but I know it's doable to build a converter.

It's not been done on these forums because it's equal in cost or more expensive than just buying monitor of that size most times.

Rekarp · Post by **Rekarp** » Wed May 13, 2009 7:56 pm

tom61 wrote:
jjhammerstein wrote:I know why it's hard, but I know it's doable to build a converter.
It's not been done on these forums because it's equal in cost or more expensive than just buying monitor of that size most times.

Exactly to build a decent composite to VGA adapter you are looking at $20-$30.

If you go straight from composite to the digital RGB and sync lines for the LCD you are looking over $70 in parts.... easiest way would to get a FPGA but those are fairly expensive. Also if you change the LCD panel the signal will need to be changed.

So yes us "EE"s have thought about it but its way to impractical and expensive when you can just buy screens that accept composite.

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Laptop LCDs as screens almost impossible, still never done?

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