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7” touchscreen works sporadically
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7” touchscreen works sporadically

by VE1JS on Wed Oct 28, 2020 6:06 pm

I have built a clock project, intended for Amateur Radio.
The screen, Adafruit 2354, works in the sense that it shows the clock and keeps good time. However, getting to other features using the touchscreen is problematic. Rarely it works but usually it does not. I get the wrong letter from the onscreen keyboard, the delete key does not work most of the time.
The screen is connected via the recommended driver board to an ESP8266 via a 20 cm extender cable.
Does anyone have any suggestions? Is there a sketch or similar that tests such screens?

Any suggestions much appreciated.

VE1JS
 
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Re: 7” touchscreen works sporadically

by VE1JS on Mon Nov 02, 2020 5:01 pm

Since no one has responded to my original post, let me try again being more specific:

The clock I have built can be seen here: http://clearskyinstitute.com/ham/HamClock/

The sketch, quite large, compiles correctly and runs nicely. The backgrounds come up as intended.

The program always starts with an opportunity to calibrate the screen by tapping 5 times in each of 3 places on the screen (always the same 3 places). This works; it counts the taps! There is a place to tap in order to skip this step, but it has yet to work for me.

Then comes the setup screen and its onscreen keyboard. Tapping a key almost never gives the desired character but rather comes up with a random character or no character; can't even count on it to give a neighbouring key. The DELETE key has to be tapped over and over again. It gives random characters and the correct one sometimes. The same for the DONE key. Nothing on this setup screen responds to a finger tap; always with a pencil, not even my iPad stylus works! Once I spend the time to fight with it and get it to work, things look great.

However, few of the very small buttons on the main screen to turn features on and off work with any consistency. The three right hand boxes at the top of the screen respond to a finger tap, but no other space responds to a finger tap.

My analysis says that I have either a defective touchscreen overlay or a defective RA8875 board, I can't tell which.

Would someone from Adafruit please take a look at this to see if they can tell which it is or if it is something else. Please contact me as required. I can take some photos if that would help.

Both parts were purchased from Elmwood Electronics in Toronto.

Thanks

John Scott, VE1JS
Sandy Cove , NS

VE1JS
 
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Re: 7” touchscreen works sporadically

by adafruit_support_carter on Fri Nov 20, 2020 8:41 pm

Hey, sorry for delayed response here.

Can you post a photo, or link to photos, of the actual hardware build. I'm not seeing anything at the link above.

It sounds like the issue is only with the touch overlay aspect of the display. Have you tried running a simple program to print out touch location results just to test the general touch behavior?

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Re: 7” touchscreen works sporadically

by VE1JS on Sun Nov 22, 2020 4:14 pm

Photo#1.jpg
Photo#1
Photo#1.jpg (10.93 KiB) Viewed 44 times
Photo#2.jpg
Photo#2.jpg (14.6 KiB) Viewed 44 times
I do not feel competent enough to write the program suggested in the above reply,.

However, I did do the following:

I wired up my Arduino Nano and used the Adafruit Library routine "buildtest"

As you can see the first part, the drawing and colours works perfectly before any touches are made on the screen.

The touching results are in the attached pix.

Photo#1: This is what I see when the program first starts. The five extraneous dots are always the the same places.

Photo#2 is what I see when I draw a more or less horizontal line across the screen with my finger nail. Lots of "noise" represented by the extraneous dots all over the place.

Photo## is the result of drawing a vertical line down the left side of the screen.

Do I have a defective screen or a defective RA8825? I can't tell.

More photos can be taken if required.,
Attachments
Photo#3.jpg
Photo#3.jpg (15.93 KiB) Viewed 44 times

VE1JS
 
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Re: 7” touchscreen works sporadically

by adafruit_support_carter on Mon Nov 23, 2020 1:49 pm

For the example you are trying to run:
https://github.com/adafruit/Adafruit_RA ... ldtest.ino
did you change this line:
Code: Select all | TOGGLE FULL SIZE
  if (!tft.begin(RA8875_480x272)) {

to this:
Code: Select all | TOGGLE FULL SIZE
  if (!tft.begin(RA8875_800x480)) {

to match your display size?

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Re: 7” touchscreen works sporadically

by VE1JS on Mon Nov 23, 2020 7:21 pm

Yes. That was done.

I'm assuming it only had to be done once in one place. Right or wrong?

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Re: 7” touchscreen works sporadically

by adafruit_support_carter on Tue Nov 24, 2020 2:44 pm

Yep, just in the call to being().

Is the display mounted in anything? Like a frame that could be stressing the perimeter parts of the touch overlay?

Those five dots:
The five extraneous dots are always the the same places.

They are in *exactly* the same place? Or just general area?

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Re: 7” touchscreen works sporadically

by VE1JS on Tue Nov 24, 2020 2:59 pm

adafruit_support_carter wrote:Yep, just in the call to being().

Is the display mounted in anything? Like a frame that could be stressing the perimeter parts of the touch overlay?

No. It is just sitting on a stand, (Originally bought and still used for holding an iPad!

Those five dots:
The five extraneous dots are always the the same places.

They are in *exactly* the same place? Or just general area?


They are very close to being exactly the same spots, but with a small amount of variability, within a few mm of the same spots. In a few recent tries there have been 5 spots most of the time, but now and then 4 or 6 spots.

I have also noticed recently that a single tap near the centre of the screen gives a spot at the tap and a widely spaced line of 8 spots rising toward the upper right hand corner of the screen. Some of these are very close to some of the 5 "native" spots.

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Please be positive and constructive with your questions and comments.