Touch Panel Project

Discussion in 'Embedded Systems and Microcontrollers' started by KansaiRobot, Sep 11, 2015.

  1. KansaiRobot

    Thread Starter Active Member

    Jan 15, 2010
    318
    5
    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.
     
    Last edited: Sep 11, 2015
  2. TheButtonThief

    Active Member

    Feb 26, 2011
    219
    38
    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.
     
  3. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,766
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    Theory of operation
     
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  4. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,498
    2,364
    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.
     
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  5. flyingdoc

    New Member

    Oct 1, 2012
    2
    1
    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.
     
  6. KansaiRobot

    Thread Starter Active Member

    Jan 15, 2010
    318
    5
    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??
     
    Last edited: Sep 15, 2015
  7. KansaiRobot

    Thread Starter Active Member

    Jan 15, 2010
    318
    5
    No replies on the question about transistors? :oops:

    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....o_O
     
  8. KansaiRobot

    Thread Starter Active Member

    Jan 15, 2010
    318
    5
  9. nestbulala

    Member

    Dec 12, 2015
    68
    1
    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
     
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