Touch screen calibration issues

I got a v4.4 kit a couple of months ago but haven’t had time to take a closer look until the past week.

Everything is working fine, except that I’ve been having problems with the touch screen.

When I’d got it, I noticed it was hard to enter characters when for instance saving snapshots, the screen would often misinterpret where I pressed, but with a bit of perseverance and judicious use of Delete it was possible to enter a name eventually.

I then ran the touchscreen calibration from the Admin menu. The calibration routine went fine, but afterwards the calibration was much worse. It’s now essentially impossible to use the touchscreen to enter characters when naming. It works when there are large fields such as the NO and YES fields, but if try to for instance use it to edit parameters the response is a bit haphazard. Pressing the screen where there is a knob graphic and sliding up and down works, sortof, but the resulting graphic is rather jumpy, and sometimes it seems to register clicks as well even though I’m holding my finger in the same area of the screen.

It’s not a big hassle for me as I’m not fond of touch screens and all UI operations seem to be accessible using the knobs (using the sequencer without the touch screen seems a bit awkward, but I’m not really interested in the sequencer for the moment at least).

I’ve noticed when bringing up the webconf that there seem to be some parameters related to the screen (in Advanced mode):

dtoverlay=piscreen2r-notouch,rotate=270
dtoverlay=ads7846,speed=2000000,cs=1,penirq=17,penirq_pull=2,swapxy=1,xohms=100,pmax=255

Are there any of this that are worth tweaking in order to improve the response?

(Today, I built another Zynthian from a v4.5 kit, and the touch screen on that unit is completely dead, so there seems to be an issue with me and touch screens… :slight_smile: ).

1 Like

Hi @ricard!

The resistive touchscreen works better with a stylus, finger is too “coarse”. You could try to run the calibration again, using a stylus and let’s see if it improves.

Regarding the broken display you seem to have received, don’t worry, i will send you a replacement ASAP.

Regards,

I redid the calibration using the stylus instead of my finger, and it works much better now. Thanks!

It even works better when I use my finger now, I can even enter snapshot names that way. So the secret seems to be to use the stylus for calibration, then using one’s finger for ordinary use will work better too.

@jofemodo Thanks for responding quickly to the (other) broken display issue!

2 Likes

BTW, i just improved touch control on testing. Now changing parameter values is smoother and MIDI learning gesture is working again.

Regards,

@jofemodo I think it would be helpful if the Touchscreen Calibration section in the UI user’s guide (Zynthian UI Users Guide - ZynthianWiki) mentioned the necessity of using a stylus when calibrating the touchscreen. (Not that I honestly actually read through this section before calibrating the screen… :slight_smile: ).

It could also be mentioned in the screen itself.

2 Likes

I just added a note to the wiki and modified the text on the touchscreen calibration screen .

Thanks!

2 Likes

Looking at the wiki with a phone the categories are collapsed and each most be opened to read. It took me a while to find the touchscreen calibration. I wonder if we should move it to the touchscreen section of the wiki?