VGA to LCD---use your laptop screen as a stand alone monitor

Recently there's been some interest in the forums about using the LCD monitor on laptops as stand alone displays capable of accepting VGA signals from any external source---an Xbox 360 or the new Asus XG Station for example. This concept would allow you to use your laptop's screen as a high quality display for any modern day electronic peripherals which sends out an analogue or digital signal for graphics. Now before anybody goes off searching for a laptop which can accept incoming video signals, let me just say that due to hardware costs and limited consumer demand it is very hard to find a laptops with VGA-IN or DVI-IN ports. However, you can do this on your own if you have the interest, and aren't afraid to void a few warranties.

To start things off, here's a few pictures and articles addressing VGA-IN to laptop LCD's. First, a picture of what it would look like:



This is from a MAKE article about doing the procedure.

So before we can just run a VGA cable from our XG Station, we need to convert the signal being carried over to LVDS (low voltage differential signaling). This is the electrical signaling format your laptop LCD accepts: you need special hardware to accomplish this for your particular brand of LCD panel. If you look on some the websites for companies dealing with embedded systems, you can find controllers which accept analogue (VGA) and even DVI input to output to LVDS. Here is an example from Kontron, this particular model is called CRTtoLCD-5:



You can check out the specs here. Also, you want to make sure that the VGA->LVDS controller is compatible with your LCD display, as not all LCD's adhere strictly to the LVDS standard.

Now we can talk about linking the hardware up. Here's a long winded, but quite informative discussion from 2005 which include some step-by-step instructions for doing this on your own. Basic soldering knowledge required, as well as the ability to tell the difference between an input pin and output pin.

Here is an example of what a finished build would look like, with more illustrations. If you are using dial-up to view this page, beware!

The extra hardware---which ranges from $70 to $200 for individual buyers---make the inclusion of a VGA-IN port an expensive idea for laptop OEM's, thus it is rare to find a laptop with the port. Lets hope the OEM's see the light and start figuring some way of bringing this hardware concept more mainstream. But if you are lucky enough to find a laptop with the included hardware, or have made the modifications yourself, then you've just added a whole new dimension of functionality to your laptop screen. And if you plan to purchase the upcoming XG Station but don't want to buy an external monitor, you are a prime candidate for this technology.