Touchscreen calibration

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wabbastang
Posts: 10
Joined: Fri Nov 15, 2019 5:37 pm

Touchscreen calibration

Post by wabbastang » Mon Jan 26, 2026 3:56 pm

Have a controller running 1.0.3. Picked up an Elo ET2201 touchscreen. Plugged in and is completely functional right away, except the horizontal calibration is off on the touchscreen. In the center, it's on. But as you touch further outward, it gets more and more off. When you touch the outer LH/RH edge of the screen, it's about an inch off.

I am trying to figure out some calibration routine. Any suggestions?

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Doug
Posts: 383
Joined: Fri Feb 02, 2018 4:56 pm

Re: Touchscreen calibration

Post by Doug » Mon Jan 26, 2026 7:21 pm

Have you tried adjusting the resolution of the monitor? My ASUS VT168H runs at 1366 x 768 resolution. You can also try adjusting the sweep frequency. Available options are usually 50hz and 60hz.

Doug

wabbastang
Posts: 10
Joined: Fri Nov 15, 2019 5:37 pm

Re: Touchscreen calibration

Post by wabbastang » Tue Jan 27, 2026 8:07 am

No, running in its 1080p native resolution in portrait mode. The touchscreen calibration problem exists exactly the same regardless of orientation, it's off in the same direction relative to the monitor itself (left/right in landscape, now up/down in portrait).

Don't know how to change frequency (specify it in /boot/config.txt?).

I see lots of info on calibration tools via libinput/xinput/evdev but I don't know what this is running and don't want to make a mess just installing junk blindly.

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Doug
Posts: 383
Joined: Fri Feb 02, 2018 4:56 pm

Re: Touchscreen calibration

Post by Doug » Tue Jan 27, 2026 3:22 pm

Can you adjust the resolution on the monitor to 1366x768? I'd am curious to see if that affects the touch position.

Be careful with modifications to the RPi linux. It would be wise to make a backup copy of the sd card before making changes.

Doug

wabbastang
Posts: 10
Joined: Fri Nov 15, 2019 5:37 pm

Re: Touchscreen calibration

Post by wabbastang » Wed Jan 28, 2026 5:45 pm

Did give that a try via /boot/config.txt and either it didn't do anything (couldn't really tell if it was scaled up to fill screen, eyes aren't as sharp as they used to be!) or it worked fine, but didn't affect the touch calibration. Thanks for the suggestions. Was excited to finally have a touch interface for doing things like calibrations and surface probing so this is bugging me to figure out.

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