Reusing old shit: lcd screen

This post is a work in progress, so if you find it incomplete and not readable probably it's not finished yet. I prefer to publish a little before than leave a post to rust in my drafts.

It’s happened in the past that someone gifted me of very old (and not working anymore) laptops that otherwise would have been thrown in the garbage; my idea for them was of reusing some parts that are more valuable: battery, disks, keyboards, etc…

One of the things more valuable are the LCD displays: the first thing to do is tear down the laptop and uncover the LCD panel itself; in the back there are few labels, one of them contains a code that identifies the model of the panel itself. Which one? I don’t know but you can try all of them, is a problem solvable in polynomial time :)

At this point you can use the site panelook.com to find the technical details: in my case the code is CLAA154WA01AQ corresponding to this model; the important parameters are the ones indicated in the image below

Signal interface

In our example we see that we need a LVDS (1 ch, 6-bit) , 30 pins , Connector

On Aliexpress you can find this cable.

Lamp type

The LCD screen needs a backlight, without it the luminance of the display is not powerful enough; technically is called inverter (probably because unlike a normal power supply, it raises the voltage, by a lot!) and is powered externally from the controller board.

The parameters that distinguish inverters from each others is the number of connectors to the LCD itself and the type: led or CCFL. In the majority of cases the second one is used.

These are links on Aliexpress (I don’t know these sellers, YMMV) just to give you an idea of what I am talking about

Controller board

Now we need something that can drive the panel from a video source: on Aliexpress you can search for it using terms like “lcd controller board”; check for the inputs you are interested in (HDMI, VGA etc…) and if it has a compliant connector for lamp type and signal cable.

One example is this one but obviously double check yourself.

Read accurately the description of the product and the resolutions supported, sometimes you can see that is possible to “update” the board with a specific firmware to support specific a resolution.

FPGA

TODO: An interesting project for the future would be to implement a LDVS controller for my mojo board.

Do you find this post incomplete? probably because it's a work in progress. Let me know how do you want this to be completed