glcdlcdtouchscreen
I know this is a very elementary question. I was wondering if it is possible to use a touch screen shield on a normal GLCD to change it into a touch-GLCD.
I have seen a product which is a transparent shield with 4 pins (something like the one covering this module
I searched google for a good tutorial on using this 4-pins device but of no avail. Can anyone give me a manual/tutorial or description?
Digitizer or touch screen/panel digitizer.
You can find them as replacements for small LCDs. For example, but these may not be suitable for your multi-touch requirement, and getting application information may be difficult.
They're typically laminated onto the LCD display, and can be removed safely with a controlled temperature hot-air gun (and care, they're usually very thin glass).
It's hard for me to imagine that your 1 big sheet of metal would work as a touch pad for 3 main reasons
Although, I congratulate you for your effort, and I'm just adding one remark
Designs for capacitive touch screens typically involve a "grid" of sensors that give x y values, but if I am not mistaken, this is only needed to register multiple touches.
No, not really. In an other post that have nothing to deal with yours, I've added 2 pictures that a touch screen controller (with image processros inside) is using as primary data. You would notice how a grid is used to capture the touched area. Imagine a big big finger touching the screen.
It would be seen on many "touch pixels", then an algorithm like a centroid detection, will compute the center (x, y) of the touch area. That's not only for multi-touch.
Best Answer
These touches work as resistive touches. the resistance changes as a potentiometer between X1-X2 and Y1-Y2 that can be calculated and translated to the position. Very good tutorials are here and here. Just search google for "resistive touch screen theory of operation" and tones of answers are there.