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 Post subject: I need touchscreen_axes_calib Help please
PostPosted: Thu Jan 14, 2016 6:55 pm 
Joined: Mon Nov 02, 2015 1:20 am
Posts: 32
Can someone please explain what each part of this file does?

No matter what I do with the numbers it stays uncalibrated.

calib_x_d=25;
calib_x_fact=0.665938864629;
calib_y_d=772;
calib_y_fact=-0.424005218526;

I would really appreciate the help.


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 Post subject: Re: I need touchscreen_axes_calib Help please
PostPosted: Thu Jan 14, 2016 8:15 pm 
Joined: Sat Apr 25, 2015 5:50 pm
Posts: 180
calib_x_d=25; --> moves the touchpoint 25 pixels to the right
calib_y_d=772; --> moves the touchpoint 772 pixels towards the bottom (772 is very much! It's hard to believe that this value could be correct! That's more than your screen's overall height, right?).

calib_x_fact=0.665938864629 and calib_y_fact=-0.424005218526 --> these are multipliers. e.g.when the touchpoint is accurate in the top left corner and goes off when you touch the lower right corner, you can correct this offset by editing these values.

I suppose that the pointer is outside of the screen because of calib_y_d=772. You should first set this value to 0 and then have a look what happens. If you can see the pointer now when touching the screen, you can estimate how much pixels the pointer is away from your finger and edit calib_x_d / calib_y_d according to your estimation.

My advice is to first correct the touchpoint to be accurate in the top left corner. When done, then move your finger to the lower right corner. You may recognize that the pointer is a bit faster or slower than your finger. To get rid of this offset, edit the values of calib_x_fact / calib_y_fact. But be careful, start with only small changes to this values. It's the most difficult (and boring) part of the whole calibration process and may take a while until it's perfect. :)

Don't forget to restart your Pi after each change.


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 Post subject: Re: I need touchscreen_axes_calib Help please
PostPosted: Thu Jan 14, 2016 11:15 pm 
Joined: Mon Nov 02, 2015 1:20 am
Posts: 32
Thank you for your reply Jack.

Here's what I get
calib_x_d=-30; = almost perfect to the upper left corner.

The farther away I get from that corner the further away the cursor gets then disappears off the right side.

calib_y_d=772; is the only way the touchscreen continues to respond. I dropped it down to 500 and it seemed to make the axis go off and still no closer to the stylus.

calib_y_d=0; touchscreen stops responding.

I have two 7 inch touchscreens and they both respond the same way.

I'm at a total loss on this.


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 Post subject: Re: I need touchscreen_axes_calib Help please
PostPosted: Sat Jan 16, 2016 1:56 pm 
Joined: Sat Apr 25, 2015 5:50 pm
Posts: 180
Ok, if
calib_x_d=-30
calib_y_d=772
results in a correct touch-recognition in the upper left corner, then you should use this setting.

gcarlyle22 wrote:
The farther away I get from that corner the further away the cursor gets then disappears off the right side.

That's the point where you have to edit calib_x_fact and calib_y_fact. If the cursor goes to far to the right, decrease the value of calib_x_fact. So if the actual value is calib_x_fact=0.665938864629; try calib_x_fact=0.6. Restart and have a look what has changed. You will need several attempts until it's perfect.


If there is also an offset in the vertical axis (y), do the same with calib_y_fact.


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 Post subject: Re: I need touchscreen_axes_calib Help please
PostPosted: Sat Jan 16, 2016 2:27 pm 
Joined: Mon Aug 10, 2015 11:52 pm
Posts: 57
Yes it can be a real pain to do... I'm never too thrilled when I have to recalibrate a screen. The only way to do it is to try and guess and change one digit at a time...unplug/replug and try again. When you do finally get the perfect numbers write them down or save it somewhere on your computer.


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 Post subject: Re: I need touchscreen_axes_calib Help please
PostPosted: Sat Jan 16, 2016 9:37 pm 
Joined: Mon Nov 02, 2015 1:20 am
Posts: 32
Thanks for your replies.

So I have been working on this for about 6 hours now.

calib_x_d=-29;calib_x_fact=0.513406303036; = perfect all the way across the screen until about 1/2 inch from the right then it jumps off the screen

calib_y_d=765;calib_y_fact=-0.423127083333; = No Matter what I do here I can't get it any closer


Here is some of what I did.

calib_y_d=765 at 765 the cursor is below the stylus about 1 1/2 inch I have taken to 500 cursor does not respond on the screen. 800 puts the cursor above the stylus buy about an inch.

calib_y_fact=-0.423127083333 I have dropped all numbers by 1 = 312016072222 no change up by 1 = 534238094444 moves the cursor to the left of the stylus.

Any Ideas?


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 Post subject: Re: I need touchscreen_axes_calib Help please
PostPosted: Sat Jan 16, 2016 10:47 pm 
Joined: Sat Apr 25, 2015 5:50 pm
Posts: 180
gcarlyle22 wrote:
calib_y_d=765 at 765 the cursor is below the stylus about 1 1/2 inch I have taken to 500 cursor does not respond on the screen. 800 puts the cursor above the stylus buy about an inch.


Seems that your your y-axis is swapped. The cursor should move to the bottom when increasing the values and upwards for lower values. That's the opposite of how your screen reacts. You should check if your touch controller is correctly connected. And please post the full content of your touchscreen_axes_calib file.

Which display do you use?

Regarding calib_y_fact: As I wrote above you should increase/decrease the values only in a small amount. When adding 0.1 is too much, try +0.05. You can cut the numbers, you will only need 3 or 4 digits after the dot. This will be precise enough.


Last edited by jack on Sat Jan 16, 2016 11:05 pm, edited 1 time in total.

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 Post subject: Re: I need touchscreen_axes_calib Help please
PostPosted: Sat Jan 16, 2016 11:05 pm 
Joined: Mon Nov 02, 2015 1:20 am
Posts: 32
Hi jack

I swapped the cable and this is what I got with no response after the calibration. It responds during but not after.


calib_x_d=8336;calib_x_fact=-29.0476190476;calib_y_d=0;calib_y_fact=-72.2222222222;swap_axes=0;click_confines=8;touch_mouse=1

This is the original

calib_x_d=-29;calib_x_fact=0.513406303036;calib_y_d=765;calib_y_fact=-0.42345276873;swap_axes=0;click_confines=8;touch_mouse=1


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 Post subject: Re: I need touchscreen_axes_calib Help please
PostPosted: Sat Jan 16, 2016 11:17 pm 
Joined: Sat Apr 25, 2015 5:50 pm
Posts: 180
I have no idea what is going wrong. These are also crazy values. Swapping the cable doesn't help.

Again: Which display do you use? Resolution is set correctly in /boot/config.txt?


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 Post subject: Re: I need touchscreen_axes_calib Help please
PostPosted: Sat Jan 16, 2016 11:34 pm 
Joined: Mon Nov 02, 2015 1:20 am
Posts: 32
Ok here is a link to the driver board:

http://www.vslcd.com/Specification/VS-TY2662-V1.pdf

My display

https://www.olimex.com/Products/OLinuXi ... 70TN92.pdf

/boot/config.txt
# For more options and information see
# http://www.raspberrypi.org/documentatio ... fig-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=480

# 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=1
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt 800 480 60 6 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=1000

# Uncomment some or all of these to enable the optional hardware interfaces
dtparam=i2c_arm=on
dtparam=i2s=on
dtparam=spi=on

# Uncomment this to enable the lirc-rpi module
#dtoverlay=lirc-rpi

# Additional overlays and parameters are documented /boot/overlays/README

core_freq=500
sdram_freq=500
over_voltage=2
dtparam=spi=on
dtparam=i2c_arm=on
disable_splash=
gpu_mem=128


If you need anything else I will be bacl later have to go to work.

And thanks again for all your help


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