Using touchscreen with qlc+ raspberry pi

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mspi
Posts: 4
Joined: Thu Sep 22, 2022 3:32 pm
Real Name: Matias

Hi! I have two problems using 3.5inch tft gpio screen with my raspberry qlc+. If somebody could please help me it would be nice :)

Some background information; i have raspberry pi 3b+ and 3.5inch touchscreen with it. I got the screen visually working with the instructions, but there is problem with touch and getting cmd after activating the screen.

So problem number 1: I cant get the screen calibrated right, it is inverted, if I press from the left edge of the screen, it will register the touch from the right edge.
Probably there is easy fix to this but im just dumb and don't get it :D

Problem number 2: When the 3.5inch screen is activated (Edited the file /etc/init.d/qlcplus like the instructions says and rebooted) i can't get back to cmd. Normally i just pressed ctrl, alt and backspace to get there, but now nothing happens. Should it be like that or have i done there something wrong too?

- If somebody know what should i change or install to get it work right it would be really nice :)
And thank you developer, its really good software :)

Thanks.
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GGGss
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Location: Belgium
Real Name: Fredje Gallon

Welcome to this forum mspi,
Hmm, L to R problems seem to reduce themselves to the screen being upside down?
All electric machines work on smoke... when the smoke escapes... they don't work anymore
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mcallegari
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Real Name: Massimo Callegari
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Screen rotation should be achieved by setting this variable when starting QLC+:

Code: Select all

QT_QPA_EGLFS_ROTATION
mspi
Posts: 4
Joined: Thu Sep 22, 2022 3:32 pm
Real Name: Matias

Hi! Thanks for all who have contributed to solving the problem.

There is video what the screen looks like: https://youtu.be/UawLCPHUDhM

But the main problem is that i cant get my way to cmd if the user interface is displayed on the touch screen (no problem if i switch it back to hdmi using ssh). And that means i cant change the wifi configuration via sudo raspi-config = i lose connections to pi from web and ssh if the wifi address or password changes. So if anybody knows how do I get to the command view with the touch screen active it would be helpful (ctrl f12 and then ctrl + alt + backspace not work)

Also i'm not sure where i should add this "QT_QPA_EGLFS_ROTATION". To config.txt, or maybe to the /etc/init.d/qlcplus file?
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mcallegari
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into /etc/init.d/qlcplus, yes
mspi
Posts: 4
Joined: Thu Sep 22, 2022 3:32 pm
Real Name: Matias

Is there specific place for it? I tried to add it line before QLCPLUS_OPTS="-platform linuxfb:fb=/dev/fb1 -plugin evdevtouch:invertx --web –operate" but nothing happened
mspi
Posts: 4
Joined: Thu Sep 22, 2022 3:32 pm
Real Name: Matias

For now only thing that i have found out is that for touchscreen working at all there should be "invertx" in QLCPLUS_OPTS line. If there isn't it wont work at all. Maybe I should invert x and y? Is there way to add "invert" and "invert" in same line?
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