No announcement yet.

What I learned about Touchscreens

  • Filter
  • Time
  • Show
Clear All
new posts

  • What I learned about Touchscreens

    So finally, I near the end of my Mp3Car journey. I could not have done it without all of the great info and people on this board.

    I am still in "beta" stage of my project, but have everything working. I had been searching for a cheap, effective way to control my carputer. I had tried trackballs, keypads, touchpads, you name it. What I really wanted was a touchscreen, but did not want to pay for an overlay and controller. My carputer is using a 6.4" LQ64D343 VGA screen with a datalux controller and some custom cables. I have an 8.4" touchscreen overlay and controller board from an old fujitsu laptop with a bad motherboard. Could I use this 8.4" touchscreen with unknow wiring on a 6.4" screen and find windows XP drivers to get it all working? It seemed like an impossible task. No one knew if it would work and most thought I was crazy for even trying it. For those of you who wish to try this, it is not at all easy.
    What I did was this:
    I traced the touchscreen controller cable to the ps/2 port in the laptop using a multimeter and a semi-educated guess. I made my own cable and wired it to the touch controller and a male ps/2 plug from radio shack. It didn't work at all. Did some research on the ps/2 port mouse pinouts and found out I was using the data lines marked "reserved" on the ps/2 port. So I moved those 2 wires to the pins marked "sync" and "data" for a mouse. Now it sort of worked. I could use the touchscreen like a big touchpad and drag the mouse cursor around. I installed every driver I could find from fujitsu, but there are no drivers for this touchscreen for windows xp. the laptop was too old and the drivers from newer touchscreen laptops for xp did not work. I hooked it all up to a machine running windows 98 installed and reinstalled different drivers a few times and finaly it worked! Now for the real problem, how could I get the software to only use 6.4" of the touch panel. I tried using the calibration util that came with the driver and would give an error "invalid parameter" I played around with it for a while and finally found a calibration program from one of the other drivers that would not error out. it worked, but I'm running xp on my carputer and don't really want to install win98 as xp goes in and out of suspend in under 4 seconds. Finally after a few more hours of downloading, installing, and reconfiguring various drivers I found a win2k driver that along with the calibration utility worked! So now I have a touchscreen that works and the touch panel fits perfectly in the case I built for the lcd.

    I hope this incredibly long explanation helps someone out there as I could not have done this without all the weird info I found.

    Will post pictures and explain the whole project when it is completed (and the jungle of wires is out of the passenger seat)

  • #2
    Thanks for the info! It's great when you finally get something working...even better is when you get something that really, by rights is not supposed to work together at all!

    Great job!

    - Jeff
    95 Mustang GT Convertible
    87 Mustang GT Convertible
    My Project | Let's Go Mets! | SCT Tuners

    Project Status [===#===] [Bezel and dash creation]


    • #3
      I'm SO proud of you. Hee hEe

      I hope to get mine done one of these days


      • #4
        did you cut the rest of the touchscreen panel to fit the screen? or bend it out of the way? (i dont know if a touch screen is like hard like glass, or soft like vinyl)
        Project AutoBoxen: Coming along, almost ready to hook up in the car.
        Celeron 500, 192mb ram, 8gb hdd, other stuff.
        '91 Mazda 626: Its free, so ill use it.


        • #5
          What fujitsu was the touchpad from...and do you know where you got the drivers from?

          current projects


          • #6
            The touchscreen itself is several layers of glass and plastic and cannot be bent or cut as it has some electrical traces etched into it. It fits perfectly in the case I had already been using (an old cd-rom drive casing painted black).

            Both the touchscreen panel and controller came out of a fujitsu B112 Lifebook laptop. Bought it for cheap with motherboard problems and was never able to find a replacement for less than the machines sell for on ebay.

            Btw if anyone has a 6.4" 4 wire resistive touchscreen for sale I'd like to reduce the size of this thing so I can mount it in my dash someday.


            • #7
              Originally posted by Charliey
              did you cut the rest of the touchscreen panel to fit the screen? or bend it out of the way? (i dont know if a touch screen is like hard like glass, or soft like vinyl)
              first, you can't bend a touch overlay, next, it would render the overlay foobar to cut off parts of it.
              I believe he just has the overlay hanging on the sides of the LCD.
              He could have used the extra 1.6 inches of overlay to have static buttons on the sides...
              I don't need no stinkin' startup-shutdown controller... That's what journalized filesystems are for...
              NavSys, the ultimate navigation app


              • #8
                Originally posted by sxpert
                first, you can't bend a touch overlay
                That's not exactly true, some overlays are thin plastic sheets, as bendable as a piece of paper
                [H]4 Life
                My next generation Front End is right on schedule.
                It will be done sometime in the next generation.
                I'm a lesbian too.
                I am for hire!


                • #9
                  Can youpost the pinout's for the touch screen i wanna use iton another 8.4" thanks =)
                  1997 Mazda 626 ES [Cronos] - 2.5L V6



                  • #10
                    which drivers did you use?

                    I'm really curious as to which drivers you used to get the touchpad working.