10" Touch Screen for Raspi on route shortly!


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by Wizard » Sat Oct 06, 2012 10:28 pm
Yep, within the next couple of days I'm unboxing my 10" (HDMI) touchscreen + LVDS from ChalkElec.

I will obviously conduct various tests and post them here since the whole package seems rather competent - and is for now the "only" way to connect a touchscreen to our beloved Raspi's, that is unless you are an employee of Broadcom or have grotesque reverse engineering skills... ;)

It's a pity we lack a binary blob for the CSI connector since I have loads of small and large panels with touch capabilities from work... But one day we might ;)

Anyhow, if you're interested in such a test please have a look in a few days.
Myself is about to have a portable Raspi "pad" for interfacing hardware and conducting "field" experiments!
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by JF002 » Mon Oct 08, 2012 7:43 pm
I can't wait to read the results of your tests!
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by Wizard » Wed Oct 10, 2012 6:51 pm
Quick update! (longer later tonight...)

Received the kit + panel tonight and quickly plugged in a Raspberry Pi and voila! :)
Looking DAMN good so far and the touch functionality is there for sure!

After a while the mouse pointer started to jump around a bit but I'm running panel + wifi without USB hub so a few "effects" are expected ;)

I will conduct tests as soon as wife and kids are sleeping and I'm using an ASUS Transformer Infinity 700 tablet as reference. (1920x1200)

CPU load is NOT affected by the kit as earlier feared by some...

Back shortly but I'm more than happy so far!
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by Wizard » Wed Oct 10, 2012 7:58 pm
Removed wifi and mouse pointer stopped jumping around - as expected ;)

I don't know what to say more than it does what it's supposed to do!
The step-by-step instruction was easy and trouble-free.
Add "hdmi_edid_file=1" in config.txt as the first line and then copy the file edid.dat to the root of your SD card - that's it!

The panel I bought with the LVDS kit is top notch and wee worth the extra $.
The driver board works really well and the only thing I'm not 100% happy with is the touch speed but I will have a look at the driver and see where the bottleneck is... I doubt it's the hardware...

Nevertheless, I can absolutely recommend the kit from chalk-elec if you need a 10" display with touch capabilities, or without touch, it really works! (and no, I'm not sponsored in any way ;) )

Next step is to dig into the sw touch driver and see what's lurking there and if things can be sped up.

Image

Image

As you can see, CPU is not affected by the kit.

A feature I like is the USB output for powering the raspi.
Cables are a nightmare when tinkering with microcontroller boards and gadgets...

Next to test is Android (driven by yet-to-be-released Sony Android phone) and see how the touch part is working compared to Raspi/Debian implementation.

My portable Raspberry Pi with touch screen is now looking realistic and apart from lower resolution, the panel is virtually as goos as my ASUS Transformer Infinity 700, and that's the best tablet available to date!

The only thing I regret is not ordering more kits... This'll be great for various projects!!!
$35 for the LVDS converter and $100 for the panel is very reasonable, especially since the panel is a high quality LG panel!

Thank you Andrew, great kit you've assembled!
The box was well padded as well since some twat had abused it whilst in transit, no worry though.
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by Wizard » Sat Oct 13, 2012 7:26 pm
Ok, I'm having fun with my display and I have now built a portable Pi!

Was really miffed about the "touchability" of X so I decided to configure a WM that more suited to touch screens.
After a lot of tinkering and looking around I'd installed and configured KDE Plasma Netbook on my Raspberry Pi.

Sadly it won't work because memory footprint... :/ Way too big RAM usage so It's back to the drawing board again.

I'm also compiling a few video clips of how-to and similar with the LVDS board and I'll post them on the tube shortly.
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by pi.heroe » Mon Oct 15, 2012 1:21 pm
that's a good job !

I'm thinking about the same project, but the cost of the screen is quite expensive, compared to an android tablet.

Can't wait your videos :)
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by vamsi4012 » Tue Oct 16, 2012 6:14 pm
hello i have a lilliput 669gl 4 wire restive touchscreen i am able to use it as a monitor for my pi but how do i get the touch to work??
thanks in advance!
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by Wizard » Tue Oct 16, 2012 9:20 pm
Videos will be available within the next couple of days. (just recently got stuck in a wheelchair after a spinal injury so I spend most of the days in bed and my wife didn't like me soldering in bed so I can only tinker when I get up ;) )

Anyhow, Just realised today that KDE Plasma Active 3 was released and since I ordered a 512MB Raspi this morning this project now seems doable!

In order to get touch working I made the following change to kernel config;:
Device Drivers --> HID Devices --> Special HID drivers
CONFIG_HID_MULTITOUCH = Y
CONFIG_HID_NTRIG = Y (for my LG touch screen)

Tonight I'm making a new image for KDE Plasma Active 3 and see if that runs ok.
If it does I'll post a link to the image!

I also built an "ugly-but-workable" plexi glass housing for all the electronics needed in order to run my portable pi and now I've got my own Rapberry Pi Tablet :)

More on this later... ;)
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by cobra52383 » Fri Oct 19, 2012 6:23 pm
I may have overlooked this in your thread, but can you post the part numbers and website of screen and board your're using?
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by Wizard » Fri Oct 19, 2012 7:05 pm
I haven't updated this thread as much as I hoped to due to being stuck in a damn wheelchair quite recently but I'm trying really hard to get KDE Plasma Active to run smoothly on my touch screen enabled Pi.

I upgraded the Pi to 512MB memory so I could dedicate a bit more to the graphics side and it helped but not enough. Damn Broadcom for being so secret but in the end that's how things work now. :/

I bought my screen and HDMI LVDS converter from chalk-elec.com
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by stephelton » Mon Oct 29, 2012 5:57 pm
Any progress to update? I'm quite interested in one of these, but the price is fairly steep (esp. with shipping) so I'd like to know that it will indeed work.

Also, how is the performance? I don't intend to run anything as bloated as KDE, but I'd really like to provide a smooth 60 fps UI.
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by Wizard » Mon Oct 29, 2012 6:21 pm
Refresh is refresh and the graphical quality is superb! No difference from any other panel I have :)

The only issue I still have is ghost events from the N-trig driver. (the mouse pointer jumps around after a while and create random touch events)
I have tinkered with a different linux board with homebrew kernel and I didn't see this here.

Anyone at Broadcom who can shed some light on the current N-trig driver in the binary blob?

I suspect this'll be the most common touch driver so it'll have to work.
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by TillM » Tue Oct 30, 2012 6:15 am
Anyone at Broadcom who can shed some light on the current N-trig driver in the binary blob?


I thought the n-trig was in the linux kernel it shows up in lsmod as hid_ntrig.
I have a feeling all the sluggishness, missed touches and phantom touches are a result of the poor usb implementation on raspi.

When I plug my screen into a regular linux computer with proper usb support it works flawlessly. Apart from multitouch that is.

Also found that calibrating the screen using xinput_calibrator helped a lot with phantom clicks. It's not in the repo's, you have to compile it yourself but it's relatively easy thing to do.
http://www.freedesktop.org/wiki/Software/xinput_calibrator

Have you got multitouch to work in any way?
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by TillM » Thu Nov 22, 2012 11:11 am
Hi wizard.

I don't know if your still following this post or working with your lg 10inch touchscreen. But I thought I'd share some developments with you.

I managed to get mine to work really smooth on my raspi by setting some settings in /usr/share/X11/xorg.conf.d.

In this directory you'll find a file called 10-evdev.conf. What I did was create another file 50-ntrig.conf and added these entries.

Code: Select all
Section "InputClass"
   Identifier "N-Trig Pen"
   MatchIsTablet "on"
   MatchProduct "N-Trig Pen"
   Driver "evdev"
   Option "Ignore"  "on"
EndSection

Section "InputClass"
   Identifier "N-Trig Touchscreen"
   MatchIsTouchscreen "on"
   MatchProduct "N-Trig Touchscreen"
   Driver "evdev"
   Option "Ignore"  "on"
EndSection

Section "InputClass"
   Identifier "N-Trig MultiTouch"
   MatchIsTouchscreen "on"
   MatchProduct "N-Trig MultiTouch"
   Driver "evdev"
EndSection

Section "InputClass"
    Identifier "calibration"
    MatchProduct "N-Trig MultiTouch"
    Option "Calibration" "9 9628 56 7171"
EndSection


I also uninstalled xserver-xorg-input-synaptics which seemed to be conflicting with evdev driver. Anyway if you uninstall this driver it will remove xserver-xorg-input-all package which will remove your keyboard and mouse driver, just reinstall them after the removal separately and all will be good again :)

It would appear that the three types of input offered by the n-trig touchscreen conflict with each other on a standard linux install without proper drivers from the manufacturer. And yet they claim to support linux?

There are more convoluted ways to configure each input, but sadly most of the code is for ubuntu only it would seem. Tied in with their new unity crap. A path I'm not will to go down, perhaps you may be interested. details can be found here.http://ubuntuforums.org/showthread.php?t=1252492

Anyway, I hope this helps you a bit. Mine works just as I want now, I'm happy :)
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by Wizard » Thu Nov 22, 2012 3:58 pm
Wow!
You've seemed to have solved the case!

I shall have a tinker with this tonight and I've been playing around with similar settings myself without glitch-free outcome so this is more than welcome.

Many thanks!
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by TillM » Thu Nov 22, 2012 4:56 pm
Beware though, if you plug a mouse or keyboard in with the touchscreen it can and often does screw things up unfortunately. The usb on the raspi still needs a lot of tender loving care, although I've noticed it's getting better somehow. One day perhaps?
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by Wizard » Fri Nov 23, 2012 7:44 pm
Apart from the odd usb fubar ghosting events the touch functionality works much better now and I'm very happy with the solution posted - big thank you!

But as long as we're having usb failures we will have to wait for a stable platform.
At the moment all sorts of bad things can happen when the pointer goes awol and kicks off 10+ touch events per second. I've had files deleted and all sorts of weird issues due to this.

But I'm feeling brave with the latest fixes and shall now mount a Raspi with 10" touch screen in the car and use it for everything you can use a small computer i a car!

I think I've got GPS solution ready-ish and although my car (Land Rover Discovery II mk2) doesn't talk CAMBUS, I should be able to wire up a few things and I've also got quite a few sensors I will add to the system. 9DOF could be funny whilst going off-road e.g ;)

For all of you looking for a really good 10" panel with high resolution and touch capabilities - I can absolutely recommend the one I bought from chalk-elec!
There are NO hdmi->lvds solutions for less money that comes even close and the panel they supply is actually really good and crisp.
Yes it costs a bit over 100$ but there's no way around this I'm afraid since quality costs money.
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by TillM » Sat Nov 24, 2012 12:49 am
But as long as we're having usb failures we will have to wait for a stable platform.
At the moment all sorts of bad things can happen when the pointer goes awol and kicks off 10+ touch events per second. I've had files deleted and all sorts of weird issues due to this.


I have a feeling this has to do with the ntrig driver and not the usb driver. The usb problems seem to cause missed taps more than anything. This is where overclocking the raspi really helps.

watching what happens in xev app while touching the screen shows that the driver is constantly sending data to the kernel in a stream when you hold your finger on the screen. Years ago I setup a touch panel on linux running some universal proprietary drivers from some guys. Their driver didn't do this but registered a true onmousedown event and then a true onmouseup event upon lifting off the screen. A stream of data was only registered when dragging your finger across the screen. Same as a normal mouse does. I've been trying to figure out how I might achieve the same with the ntrig driver. It might have to be done at the application level, which is a pain because you want it working this way globally.
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by JF002 » Sat Nov 24, 2012 11:32 am
Hi!

As I said in another thread, I received my touchscreen and I'm experiencing the same troubles with the touch part of the screen;

I'm creating an application in Qt/QML. My main problem is that I'm using a grid view. On a grid view, you can click on a cell or make it scroll up/down by dragging the finger accros the grid.
Using the touchscreen, it very hard to make a single click, touch is always interpreted as a 'click and move' event.

Another problem is when you keep the finger on the screen. I see the CPU utilization goind up to 100% and the cursor flickering...

I hope this could be fixed one way or another... I saw that there was some sources in the kernel tree (Linux/drivers/hid/hid-ntrig.c). I don't know much about linux drivers, but it would be worth to take a closer look.
Do you know if the driver is based on a proprietary firmware or if we all all the necessary source to fix it?
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by JF002 » Sat Nov 24, 2012 12:46 pm
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by TillM » Sat Nov 24, 2012 4:31 pm
Do you know if the driver is based on a proprietary firmware or if we all all the necessary source to fix it?


Having read through most of the stuff on the ubuntu forums, I came to the conclusion it has been reverse engineered from windows firmware. I could be wrong though.

Thanks for the link to those tools, JF002. I compiled and ran but they made little difference for me.
All that stuff about filtering and all was a great read, but in typical linux fashion, they say a lot but never really tell you what you're suppose to do. I guess I should RTFM eh? :roll:
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by goingmad » Sat Nov 24, 2012 6:33 pm
Great thread!

Ordered the 10" kit as well, planning to embed it in a brewing control panel.
Thanks for all your precious efforts also while in bed! [good luck!]
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by JF002 » Sun Nov 25, 2012 8:52 am
TillM wrote:
Thanks for the link to those tools, JF002. I compiled and ran but they made little difference for me.
All that stuff about filtering and all was a great read, but in typical linux fashion, they say a lot but never really tell you what you're suppose to do. I guess I should RTFM eh? :roll:


Yeah, I also tried to run them. At first, they did nothing because they were trying to connect with a USB device ID 1 while mine is 7. But even after modifying the sources and recompiling them... I saw no difference.

An about the filtering stuff, I tought exactly the same as you... A lot of interesting bla-bla, but no indication on how to proceed.

I would like to try the settings, but I've no idea on how to modify them. I need to learn a little on linux drivers, sysfs and all these things.
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by TillM » Sun Nov 25, 2012 10:25 am
Ordered the 10" kit as well, planning to embed it in a brewing control panel.


Beer?

I just finished running off 180 liters of wort through my 2 inch boka :)
I have an arduino connected to it to monitor the temps and have a raspi taking to it via rs485 and updating several computers on my home network so I can see what's going on from anywhere in the house :)

Eventually it will all hook into my low power touch screens so I can control it and the house all at the same time.
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by JF002 » Tue Dec 04, 2012 8:10 pm
Ok, I found an entry in /sys that seems to correspond to the ntrg driver :

Code: Select all
/sys/module/hid_ntrig/parameters


There, I found all the settings that are described in the linked I posted previously.

I tried to read/write them with no nearly succes...

Here is how I proceed :
Code: Select all
cd /sys/module/hid_ntrig/parameters
sudo su
cat  activate_slack
echo 10 > activate_slack


    sudo su: needed to be able to write the values into parameters
    cat xxx : read the value of the parameter
    echo yy > xxx: write yy in xxx

But my main problem is not the lack of multitouch of "ghost events" (I see a lot of thread about these on the web) but the fact that a lot of useless "MotionEvents" are triggered once I push a finger on the screen and don't move it (you can see that with xev).
Consequences are that a simple click is always handled as a drag/drop action and that it's really not easy to make a simple click or a double click.

I really want to use this touchscreen with an application I'm developping with QtQuick but for now, it's a little tricky to click on an item in a listview/gridview.

Any idea, help, support,investigation,... are welcome :)
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