Hello everybody and thanks always for the help.

Having concluded the previous project, the next seems to be involved with "touch panels".

As always this first post is rather general. Nothing specific. I would like to know where to get more information about these touch panels (or screens), how to control them (if I can do it with my old PIC, better) ,etc. Now , I know someone could say "there are many types, you have to be more specific". Well in the past I worked briefly with one as a display of a ARM microcontroller, but now I am more interested in general information about these, and if I can and how to use it with PICs (or AVRs if needed) .

what is the state of the art in touch screens?? color, B/W???

Thanks again for any comment, help, advice that can guide me to the right path.

 

When you say "state of the art" touch panel, I immediately think of something like the Siemens TP700.

However, it's an industrial interface for a PLC so I doubt it's what you want.

 

Theory of operation

 

what is the state of the art in touch screens?? color, B/W???

The nature of the display has nothing to do with the touch screen, in fact you can get add on touch screens to place in front of a TFT/LCD screen etc.
The screen and the touch panel are two separate items.
A source is Earth LCD Co.
Two types of touch are resistive and capacitive.
Max.

 

Have a look at <www.adafruit.com> for a neat 2.8" TFT touch screen, both resistive and capacitive versions. About US$46 plus delivery.
Well supported with documentation and software.

 

Thank you for your comments.
I have been browsing around and found this resource

http://www.mikroe.com/downloads/get/479/en_mikroe_article_c_pic_01_09.pdf

(I think this was the basis for this thread on this forum:
http://forum.allaboutcircuits.com/threads/problem-with-touch-panel.58615/ although that thread never got resolved and the original author left in 2012)

and later I found this other one:

http://www.robotsreloaded.com/p/interfacing-4-wire-resistive.html

Now, first a question about schematics.
Why do you think the first project uses transistors and stuff to drive the four "pins" of the touch screen, while the other project connect these directly to the IC pins? Are one of these preferable?

now question about the firmware:

Both of these projects basically calculate the X and the Y of the "touch", so I guess that discard multitouch, and also, these projects stop there (calculating the X and Y). How can these be useful if I want to say use not only simple touchs but also other finger interactions with the screen??

 

No replies on the question about transistors?

Anyway, about the other question, I found that resistive touch panels dont support multitouch. am I wrong?

Also about the last question, I found an article in a local magazine (frome 2010 actually) (also that article schematics didnt use transistors as my first question)that provides "buffers" in order that the tracing of curves with a finger can be smooth... the article came with some code. They talked also about double taps and drag but no code for that. so I guess it is possible.

Enough of theory, I am now wondering what resistive touch panel I should acquire to start experimenting with my PIC micro....

 

 

No replies on the question about transistors?

Anyway, about the other question, I found that resistive touch panels dont support multitouch. am I wrong?

Also about the last question, I found an article in a local magazine (frome 2010 actually) (also that article schematics didnt use transistors as my first question)that provides "buffers" in order that the tracing of curves with a finger can be smooth... the article came with some code. They talked also about double taps and drag but no code for that. so I guess it is possible.

Enough of theory, I am now wondering what resistive touch panel I should acquire to start experimenting with my PIC micro....

Hello KansaiRobot,
You can start with TFT-LCD Module from Stone-hmi.com with little command set from PIC Microcontroller well documented with controller board model ST1070WT-01.
Nest