Touch location on PT2 needs calibration / registration

[jrconlin]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

The touch point registration seems to be off. Touches to the bottom left and right corners are registered to the top of the screen. Touching the bottom middle appears to locate correctly.

I believe that this is similar to the previously closed bug #1494, so I'm not sure if this is a regression.
Since this might be a per-device problem, is there a way to calibrate the screen per device?

The attached image uses a paint program and shows lines being drawn horizontally across the device, starting at the top and progressing down the screen.

Expected Behavior

Touches at all points on the screen are registered close to the actual location.

Steps To Reproduce

Load any app registering touch screen access (e.g. Time2Paint, Two Tap Timers, etc.) Note touches at bottom left and right are registering higher on the display.

Version

v4.36.2

Host OS

N/A

Watch

Pebble Time 2 (Obelix)

Anything else?

No response

[z4q74j97fx-tech]

I have a very similar issue. I reported the bug through the app waited a month and was asked to draw a grid using the same program. Was told it was a manufacturing defect and they sent me a replacement.

[jrconlin]

Huh. Honestly, the touch thing isn't a deal breaker for me. I don't need fine resolution either (just 9 point would be fine) It really does feel like something that the software could calibrate for, but I've not dug into the code.

[z4q74j97fx-tech]

Yeah it's weird, I don't get it either. My touchscreen worked fine out of the box but at some point during the first week the screen lost its calibration. I would think you could recalibrate that, but I guess not.

[AwesomeNova]

You might need to fill out a bug report on the app to get a replacement. A while ago I filled out one for the touch calibration issue, which affected the right side of the screen. I was told it may be caused by a software bug, and considering my skills in embedded systems from university, I figured I could fix it myself. However, documentation on the touchscreen controller, the CST816, is severely lacking and makes no mention of any touch calibration settings. At that point, I gave up and assumed the touch calibration is done at the factory.

I ended up getting a replacement after sending a follow up message to the bug report asking for any progress.

[jrconlin]

Thanks!

Like I said, having fine grained touch isn't really important to me. When I used to do signal processing, we'd do the calibration in the driver and essentially add a multiplier to the portions of the signal that were weakest. It wasn't great, and fidelity suffered, but it got us a reasonable fix without replacing hardware, which was kind of out of the question. I guess that's why I was thinking that some form of calibration could be used. I wouldn't be able to reproduce the Mona Lisa on my wrist, but apps could tell if I tapped somewhere in the "dead zone" at least.

I'd dig into it more but I'm not exactly great with user interface stuff, but perhaps someone far smarter can deal with that part.

goes off to ponder

[z4q74j97fx-tech]

You might need to fill out a bug report on the app to get a replacement. A while ago I filled out one for the touch calibration issue, which affected the right side of the screen. I was told it may be caused by a software bug, and considering my skills in embedded systems from university, I figured I could fix it myself. However, documentation on the touchscreen controller, the CST816, is severely lacking and makes no mention of any touch calibration settings. At that point, I gave up and assumed the touch calibration is done at the factory.

I ended up getting a replacement after sending a follow up message to the bug report asking for any progress.

Yeah, but what I don't get then how it goes from being calibrated at the factory to uncalibrated later. Maybe it's a bug that happens during a firmware update they they only recently fixed?