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 Post subject: Sainsmart 7" eGalax touch can't set the right calibration
PostPosted: Thu Dec 17, 2015 12:33 am 
Joined: Fri Sep 18, 2015 1:30 am
Posts: 24
Hello guys,

I had a sainsmart 7" egalax touchscreen and all calibration are sick

I cant clibrate accurate, everytime I try, the axis are never near to my finger...

The x,y inverse are correct (swap the white and black wires) but, still can't do a accurate calibration...

Someone can help? Maybe a default calibration?

thanks


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 Post subject: Re: Sainsmart 7" eGalax touch can't set the right calibratio
PostPosted: Thu Dec 17, 2015 9:25 pm 
Joined: Sat Apr 25, 2015 5:50 pm
Posts: 180
If you want help, you should give us more info!
- What have you done so far to install and calibrate the screen?
- Settings in /boot/config.txt are correct?
- what's in /home/pi/touchscreen_axes_calib?
- what is the native resolution of this display? (You can't expect that everybody knows this)

There are already a lot of threads in this forum regarding this topic. And you didn't find any helpful post?


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 Post subject: Re: Sainsmart 7" eGalax touch can't set the right calibratio
PostPosted: Fri Dec 18, 2015 12:00 am 
Joined: Fri Sep 18, 2015 1:30 am
Posts: 24
Hello Jack, thank you for your help

Sainsmat 7" eGalax 800/640 and in kodi are 1280/720 and in raspbian same (1280/720)

- I'm try calibrating with kodi addon only

- Settings in /boot/config.txt are in 1280/720

- what's in /home/pi/touchscreen_axes_calib - after my post I tried to change some parameters, and in kodi the calibration is almost perfect now, x=-35 and y=-75 (the other numbers like 0.678945 no makes sense to me so far... but I guees it's the key to solve the last trouble.)

At last in certer screen are perfect, but in borders are 2~5mm error do a side or another (only in kodi, raspbian are not accurate at all)...


The calibration only works if I edit touchscreen_axes_calib

So, I'm use raspberry pi 2, wheezy with kodi 14.2

Maybe you can explain these other numbers (0.67859483) will solve kodi at all!

Thank you


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 Post subject: Re: Sainsmart 7" eGalax touch can't set the right calibratio
PostPosted: Fri Dec 18, 2015 6:37 am 
Joined: Sat Apr 25, 2015 5:50 pm
Posts: 180
Why do you set the resolution to 1280*720 (16:9) when the display has 800*640 (5:4)? You should correct this first.

In /boot/config.txt you should edit/add this:

# uncomment to force a specific HDMI mode (here we are forcing 800x480!)
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt 800 480 60 6 0 0 0

And regarding the touchscreen_axes_calib:
First you should edit the calib_x_d and calib_y_d not to be accurate in the middle of the screen but to be accurate in the top left.
Then, when your touch point goes off when moving towards the lower right corner, you have to adjust the values for 'calib_x_fact' and 'calib_y_fact'.


Last edited by jack on Fri Dec 18, 2015 7:05 am, edited 1 time in total.

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 Post subject: Re: Sainsmart 7" eGalax touch can't set the right calibratio
PostPosted: Fri Dec 18, 2015 7:00 am 
Joined: Sat Apr 25, 2015 5:50 pm
Posts: 180
Oops, sorry, I posted the wrong values for the config.txt above. I will post the correct ones later (I'm [email protected] at the moment).

Edit:
Ok, I'm back again. Here are the correct values for the config.txt:
Uncomment (remove the #) and edit this:
hdmi_group=2
hdmi_mode=87 #self defined resolution

Add this:
hdmi_cvt 800 640 60 4 0 0 0

For explanation: the config.txt is read by Raspbian during boot process. Because you didn't set the correct values here, Raspbian was not able to display the correct resolution for your screen.


2nd Edit:
in addition to above edit this:

# uncomment to force a console size. By default it will be display's size minus
# overscan.
framebuffer_width=800
framebuffer_height=640
framebuffer_depth=16

Ok, after all this edits this post may look a bit confusing. Therefore, to make it short, this is how your config.txt should look like:

Code:
# For more options and information see
# http://www.raspberrypi.org/documentation/configuration/config-txt.md
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
framebuffer_width=800
framebuffer_height=640
framebuffer_depth=16

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=87
hdmi_cvt 800 640 60 4 0 0 0

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800


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 Post subject: Re: Sainsmart 7" eGalax touch can't set the right calibratio
PostPosted: Sat Dec 19, 2015 1:59 am 
Joined: Fri Sep 18, 2015 1:30 am
Posts: 24
hello Jack, thank you for your reply and explanation! it's helpfull!!

but, I see in another thread the resolution (I don't know exactly why) need to be set 1280x720...
If set in 800x640 the screen are out and the kopdi center logo and another screen features goes wrong too...

In kodi the calibration is almost perfect, my trouble is the diference kodi - raspbian. All my set work ok but in raspbian its the problem...

Question: Kodi has a one calibration config and raspbian has another? Why?

my config file is different about that you post before...

I'll copy this and post here:


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 Post subject: Re: Sainsmart 7" eGalax touch can't set the right calibratio
PostPosted: Sat Dec 19, 2015 2:27 am 
Joined: Fri Sep 18, 2015 1:30 am
Posts: 24
Code:

calib_x_d=-25;calib_x_fact=0.66847826087;calib_y_d=-80;calib_y_fact=0.424050632911;swap_axes=0;click_confines=8;touch_mouse=1








and the boot config:

Code:
For more options and information see
# http://www.raspberrypi.org/documentation/configuration/config-txt.md
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=25
#overscan_right=25
#overscan_top=25
#overscan_bottom=25

# uncomment to force a console size. By default it will be display's size minus
overscan.
framebuffer_width=1280
framebuffer_height=720


# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=1
hdmi_mode=4

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
arm_freq=900
core_freq=250
sdram_freq=500
over_voltage=0

#video codecs
decode_MPG2=0xb61b03d3
decode_WVC1=0x9c1d8bb1
dtparam=i2c_arm=off
device_tree=


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 Post subject: Re: Sainsmart 7" eGalax touch can't set the right calibratio
PostPosted: Sat Dec 19, 2015 10:17 am 
Joined: Sat Apr 25, 2015 5:50 pm
Posts: 180
rubensx wrote:

but, I see in another thread the resolution (I don't know exactly why) need to be set 1280x720...
If set in 800x640 the screen are out and the kopdi center logo and another screen features goes wrong too...

In kodi the calibration is almost perfect, my trouble is the diference kodi - raspbian. All my set work ok but in raspbian its the problem...


Maybe 1280x720 is working for a different display, but it doesn't work for your display. 1280x720 and 800x640 have different aspect-ratios (16:9 vs 5:4). Maybe this other screen supports up- or downscaling and your's doesn't. Who knows?

So you first should tell Raspbian the correct parameters for your display by entering them in the config.txt. Kodi has it's own screen-resolution settings, which overwrite Raspbian's settings. Therefore calibration is working in Kodi, but doesn't work in Raspbian because of wrong screen settings in Raspbian.

I can't do more than recommend you to try the settings in config.txt I mentioned above. The most important settings are:
Code:
framebuffer_width=800
framebuffer_height=640
framebuffer_depth=16

hdmi_group=2 #defines DMT as HDMI-type
hdmi_mode=87 #selfdefined resolution because 800x640 is not in the list for common resolutions
hdmi_cvt 800 640 60 4 0 0 0 #setting of width,height, framerate, aspect-ratio and some more stuff


Just try it! You can make a backup of your config.txt before editing, so you can revert it to the state before if something goes wrong.


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 Post subject: Re: Sainsmart 7" eGalax touch can't set the right calibratio
PostPosted: Sat Dec 19, 2015 8:27 pm 
Joined: Fri Sep 18, 2015 1:30 am
Posts: 24
Ok, I tried this...

Goes bad, the resolution are wrong and distorted... calibration still wrong too

back to 1280x720... same problem


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 Post subject: Re: Sainsmart 7" eGalax touch can't set the right calibratio
PostPosted: Sat Dec 19, 2015 10:36 pm 
Joined: Sat Apr 25, 2015 5:50 pm
Posts: 180
Are you really sure that the display has a resolution of 800x640? I did a quick search on google and only found a 7" Sainsmart display which has a resolution of 800x480!


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