Custom pen tablet pc laptop combination

Edit: I’ve updated it! I made a better case/support system for it. Check out the update here.

I’ve been fiddling around with this old pen tablet I had laying around. With old I mean véry old. It uses a COM and a PS/2 port instead of USB, to control the movement of the cursor and click events etc.

Now, together with this tablet, I had several old LCD panels somewhere on a shelve. What about combining them?

The specific info of the first beta version of the “pen screen” is as follows: The tablet itself is a CalComp Design Station Pro. Very old, and I don’t think you can get it anywhere by now, except maybe a museum…

The first beta-version pen tablet-screen-combination is made up of 2 other screens… The layer that actually adds the coulor to the light, is from a  Samsung 151s LCD panel, and is controled by it’s original PCB(Printed Circuit Board). The backlight which is underneath it, comes from another panel, because the original Smsung inverter was broken, so I had to use anotherone… I don’t quite remember what screen that was, but that doen’t really matter. You should know, that in order to let the backlight light up, I had to give it a videosignal, using another computer… The Samsung screen was hooked up to the same computer as the tablet was.

Oh, how embarassing, missing picture...

Okay, fun, but after a day or so, some part gave up, and it stoped working.

The hardest part in making this thing was, getting a good LCD pannel that was usable. The point with most panels, is that they are made in a way, that the controling PCB has to be underneath the screen. That wouldn’t work with this tablet, because as soon as there is anything metal, or PCB-like on it, it stops working.

Ok, fine, I had a verry old laptop somewhere, a Compaq Persario 700, and it’s screen turned out to be suitable to use with this tablet. But, it didn’t have a COM port, so there was no way of connecting my tablet to it. Damn.

Now, I got this very old laptop from my grandma, a Sky 7321 laptop, and it happened to have a COM port. Yey. But, when I took a closer look at the screen, it turned out not to be usable with my tablet. Damn.

But, hey, let’s combine them! I took the screen of the Compaq, that turned out to have the same connetctor as the Sky laptop, and swapped screens.

Oh, how ambarassing, missing picture...

Before, I managed to kill two LCD screens by doing the same swapping-thing, so, fingers crossed, switch on. I’t works! Huray, now al the parts are present, lets get to work.

I unscrewed everything that neede to be unscrewed, positioned it in such a way that it might not explode when I’d switch it on, connected the powersupply(PSU), and swithed it on.

Whoo, we have a booting laptop, a working screen, and a working tablet! The layer order is as follows: On the floor, there is the tablet. On the tablet, there is a backlight for the screen, with all the metal extracted from it. On the backlight, there is a layer(the actual screen), that filters the light, so that only the colors sent by the computer come through, which forms an image. From this layer, all the PCB’s have to be as far away a possible from the tablet, to aviod interference of the electric signals with the tablet. On top of that layer, there is(not yet in the above video), a plate of glass, to avoid pressure on the screen when clicking(pressing) with the pen.

Problem is the alignment. As you can see on the video, the cursor goes quite anywhere exept where I want it to go, and the pen-sensitive area goes beyond the screensize. But, enough hope to continue.

Next, I wanted to make this heap of electronics a bit organized. I placed the tablet on the body of the laptop, put a thin glass-plate on top of the screen to avoid making dead pixels when pressing with my pen, and booted it again. Before I made the next vid, I set the sensitive area of the tablet to the same size and location as where the screen was fixed(with a glue-gun), so that the movement of my pen corresponds with the movement of the cursor. To do this, I just used the TabletWorks(original) driver/utility.

Next, I thought that the whole thing was to big, heavy, and not so easy to handle. So I took the whole laptop apart, detached quite anything that wasn’t strictly neccesary, and mounted it on the back of the pen tablet.

Here is a set of photos showing the taking apart and mounting process(zip, 16MB).


Oh, how embarassing, missing picture...

Allright, so now I have a pen screen, with a build in computer! But, sadly enough, it’s not powerfull enough to run anything like Photosop or GIMP or whatever. Damn.

But there’s a solution. It’s called VNC, and lets you control one computer through another. So, I installed the VNC sever on my desktop, and the client on the pen screen PC, so I could control my dekstop with my tablet. This is not only a solution, but it also makes the tablet crossplatform compatible, because there are VNC servers/clients for every OS!

Here’s a HD video of me, fiddling around on my desktop, via my tablet, playing with Photoshop.

As you might see, the framerate is far below comfortable, and definitly not suitable for gaming(yes, I tried… Minecraft), but for Photoshop, it works, if you’re not to impatient.

Aditional info:

The laptop is running on a 1.2Ghz AMD Athlon CPU, and it has 256MB memory. Just enough for windows XP.

I’m sorry for the terrible quality of some of the vid’s/pic’s, but they were taken with a pocket cam, because I didn’t have anything else at hand.

My desktop is a 2.83Ghz quadcore, so some lagging frames with the VNC are definitly because of a somewhat slow connection/slow laptop…

The cursor via VNC doesn’t update if you don’t move it. At the end of the last video, when I save my work, you see the cursor hangs at the sandglass/hourglass, and only changes when I start moving it again.

On this picture you see the ribbon cable that keeps the PCB’s from being folded away underneath the screen. This means that this screen is not usable for placing on my tablet.

Oh, how embarassing, a missing picture...

The first draft of this thing was inspired by the Wacon Cintiq, the same principle, but very expensive…

If anything is unclear, or you want aditional information/pictures, please leave a comment.

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