bobross62
Posts: 9
Joined: Mon Jan 26, 2015 6:48 pm

Touch Screen Calibration

Mon Sep 28, 2015 12:10 am

I have my official 7" touch display running - but the finger touch point and the cursor position are at least 1/2 inch different. There must be a calibration routine - but where....

Also I downloaded the soft keyboard, are there different keyboards to down load?

Thanks
Bob

gadgetoid
Posts: 152
Joined: Wed Mar 07, 2012 9:58 pm

Re: Touch Screen Calibration

Mon Sep 28, 2015 12:57 pm

As far as I'm aware there's no calibration process. Have you tried a freshly imaged and updated install of Raspbian to eliminate the software being at fault?

bobross62
Posts: 9
Joined: Mon Jan 26, 2015 6:48 pm

Re: Touch Screen Calibration

Mon Sep 28, 2015 1:23 pm

Yes all brand new PI2, fresh downloaded raspi -

Bob

gadgetoid
Posts: 152
Joined: Wed Mar 07, 2012 9:58 pm

Re: Touch Screen Calibration

Mon Sep 28, 2015 1:26 pm

Need to /summon @gsh to see if he can shed any light on a possible calibration process, this isn't a problem I've seen before.

MikeDunn
Posts: 81
Joined: Wed Jul 01, 2015 6:58 pm

Re: Touch Screen Calibration

Mon Sep 28, 2015 5:00 pm

Hi Bob,

Glad it's not just me ! Thought I must have been doing something wrong ... !

Do we need any particular exotic items to /summon @gsh ? :lol:

Mike

gadgetoid
Posts: 152
Joined: Wed Mar 07, 2012 9:58 pm

Re: Touch Screen Calibration

Mon Sep 28, 2015 5:17 pm

MikeDunn wrote:Hi Bob,

Glad it's not just me ! Thought I must have been doing something wrong ... !

Do we need any particular exotic items to /summon @gsh ? :lol:

Mike
You mentioned elsewhere that your screen resolution is reporting as "752x448". This would be congruent with the touchscreen not registering properly.

@Bob, could you check and see if you're also seeing this resolution. It's in the menu somewhere and I don't have a Pi or Touchscreen at home to give you precise instructions, but it would be very interesting to know if these two things coincide.

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1317
Joined: Sat Sep 10, 2011 11:43 am

Re: Touch Screen Calibration

Mon Sep 28, 2015 5:22 pm

The touchscreen is supposed to be calibrated at source, although there is a mechanism to recalibrate I think it then happens somewhere in the input driver...

I'd suggest running evtest to find out what the touchscreen driver is actually saying...

if the numbers from the driver are the same then I'd suggest it's a badly calibrated touch screen... I believe you should be able to use ts_calibrate to fix though

Gordon
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

gadgetoid
Posts: 152
Joined: Wed Mar 07, 2012 9:58 pm

Re: Touch Screen Calibration

Mon Sep 28, 2015 5:23 pm

I found a reference to the screen resolution issue elsewhere, this could be the problem: viewtopic.php?f=63&t=120260

So give this a try:
FlyingKipper wrote:Yes you have Overscan setting enabled.
run raspi-config
then select Advanced Options -> Overscan -> Disable
Edit: If this works, I'll add it to my growing-and-badly-in-need-of-some-structure FAQ

bobross62
Posts: 9
Joined: Mon Jan 26, 2015 6:48 pm

Re: Touch Screen Calibration

Mon Sep 28, 2015 5:29 pm

It sure Sounds like it - Will try tonight

MikeDunn
Posts: 81
Joined: Wed Jul 01, 2015 6:58 pm

Re: Touch Screen Calibration

Mon Sep 28, 2015 6:05 pm

Yup - fixing the overscan has fixed the touch offset - well, for me anyway !

Cheers all !!! :D

Mike

bobross62
Posts: 9
Joined: Mon Jan 26, 2015 6:48 pm

Re: Touch Screen Calibration

Tue Sep 29, 2015 12:12 am

Yep Fixed -

under the preferences tab is the monitor - it showed 752x448 wrong! After the raspi-config it's 800X480

run raspi-config
then select Advanced Options -> Overscan -> Disable

Thanks
Bob

User avatar
ab1jx
Posts: 668
Joined: Thu Sep 26, 2013 1:54 pm
Location: Heath, MA USA
Contact: Website

Re: Touch Screen Calibration

Sun Feb 25, 2018 6:41 pm

gsh wrote:
Mon Sep 28, 2015 5:22 pm
The touchscreen is supposed to be calibrated at source, although there is a mechanism to recalibrate I think it then happens somewhere in the input driver...

I'd suggest running evtest to find out what the touchscreen driver is actually saying...

if the numbers from the driver are the same then I'd suggest it's a badly calibrated touch screen... I believe you should be able to use ts_calibrate to fix though

Gordon
This is a big can of worms for some reason. I ran evtest and I tried this on all 4 sides: start with my finger beside the display then drag it back onto the display until evtest first displayed something. The numbers look right: x=0 at the left, x=799 at the right, y=0 at the top, y=479 at the bottom.

Yet if I just touch the display I can't get the pointer to go below about 3/4 inch from the bottom. I'm using LXDE and I can't reach the Menu button or the pager, anything on the bottom row. With another pointing device (bluetooth iPazzport's touchpad in this case) I can move the pointer all the way to the bottom of the screen.

And my /usr/share/X11/xorg.conf.d/99-calibration.conf file acts as though it's not being read. I can delete it and reboot, it makes no difference. I created it with xinput_calibrator. Trying ts_calibrator when I can get it to work right. Do these calibrators function at different levels? I think it's different layers of software. evtest and evemu-record give reasonable mumbers, it's something to do with evdev and lbinput.

hmm, from man evdev: "evdev is an Xorg input driver for Linux´s generic event devices". From man libinput: "libinput is an Xorg input driver based on libinput". Maybe my mistake is having both of them installed, maybe one was supposed to replace the other.

Bingo: https://www.reddit.com/r/archlinux/comm ... and_evdev/ Evdev is kernel level, libinput handles fancier stuff.

I did apt-get remove libinput-bin and I see these things are depending on it: libinput-bin libinput10 xserver-xorg-input-all xserver-xorg-input-libinput so I'll wait for now. But libinput is my prime suspect. Finally took it out, the pointer was stuck at 0,0 until I put back xserver-xorg-input-libinput. Then same as before, I can point to all the edges except the bottom.

I solved it by using a calibration matrix but back to my original thread at viewtopic.php?f=108&t=205569&p=1277999#p1277999

Return to “Official Foundation Display”

Who is online

Users browsing this forum: No registered users and 3 guests