Touchscreen Jumpy

[mingu2001]

So, I have bought a touchscreen from Aliexpress, https://bit.ly/2Nwt2V4,
which is the same thing as a Waveshare 5 inch LCD, just from a different distributor.
I have connected it to my raspberry pi and installed the drivers, and even calibrated the touchscreen.
However, when I go to touch something, moving or holding down the cursor makes it jump around.
I did connect a DAC on the same 5v and ground that the touchscreen is using, if that makes any difference.
Maybe the DAC is interfering with the ground?
What may be the cause of this? How can I fix this?
Thanks in advance!

[DirkS]

I did connect a DAC on the same 5v and ground that the touchscreen is using, if that makes any difference.
Maybe the DAC is interfering with the ground?

Have you removed the DAC to find out if it makes a difference?

[mingu2001]

Have you removed the DAC to find out if it makes a difference?

I tried moving the DAC GND pin to one which the screen does not use, and it seems to make no difference.
And, if DAC was causing it, it would have at least some correspondence with audio output from the DAC, but there seems to be none.
Even with the DAC not producing any audio, it makes the noise.

[DirkS]

Have you removed the DAC to find out if it makes a difference?

I tried moving the DAC GND pin to one which the screen does not use, and it seems to make no difference.
And, if DAC was causing it, it would have at least some correspondence with audio output from the DAC, but there seems to be none.
Even with the DAC not producing any audio, it makes the noise.

Why are you asking for advice? You seem to have all the answers alreay.
Good luck with solving your problem.

[mingu2001]

Why are you asking for advice? You seem to have all the answers alreay.
Good luck with solving your problem.

Are you suggesting that the problem is the display itself, and I would need to replace it in order to fix the problem?

[DirkS]

Why are you asking for advice? You seem to have all the answers alreay.
Good luck with solving your problem.

Are you suggesting that the problem is the display itself, and I would need to replace it in order to fix the problem?

No, I was suggesting to completely remove the DAC to see if it has anything to do with the problems you see.
Just diagnostics for now.

[mingu2001]

Why are you asking for advice? You seem to have all the answers alreay.
Good luck with solving your problem.

Are you suggesting that the problem is the display itself, and I would need to replace it in order to fix the problem?

No, I was suggesting to completely remove the DAC to see if it has anything to do with the problems you see.
Just diagnostics for now.

The problem persists even after I remove the DAC completely from the pi.

[DirkS]

Now you know it

You say you installed drivers. Which ones exactly? AFAIK all the drivers it needs are already present in standard Raspbian releases.

TBH: I have a feeling there may be 2 drivers competing.
Or it could be there is something wrong with the calibration.

[mingu2001]

Now you know it

You say you installed drivers. Which ones exactly? AFAIK all the drivers it needs are already present in standard Raspbian releases.

TBH: I have a feeling there may be 2 drivers competing.
Or it could be there is something wrong with the calibration.

Since this is not an official raspberry pi display, as stated in OP, it provides a driver which you can download from here.
https://www.waveshare.com/wiki/5inch_HDMI_LCD
So I followed the instructions, and that's how you get the touch working on this display.
Without the drivers, the screen is not even detected as a touch input.
I also followed the calibration instructions in the page as well.
Even tried the Raspbian image with the drivers preinstalled.

[DirkS]

Without the drivers, the screen is not even detected as a touch input.

Well, that's all about configuration, not drivers.
The driver for the touch part of the screen has been in Raspbian for years...
Personally I'm not a fan of the waveshare method of manipulating
It may have changed, but in the past they managed to make all sorts of unwanted changes to e.g. config.txt

Apart from what I mentioned in my last post I have no additional ideas on what could be going on.

[mingu2001]

Without the drivers, the screen is not even detected as a touch input.

Well, that's all about configuration, not drivers.
The driver for the touch part of the screen has been in Raspbian for years...
Personally I'm not a fan of the waveshare method of manipulating
It may have changed, but in the past they managed to make all sorts of unwanted changes to e.g. config.txt

Apart from what I mentioned in my last post I have no additional ideas on what could be going on.

Code: Select all

max_usb_current=1
hdmi_group=2
hdmi_mode=87
hdmi_cvt 800 480 60 6 0 0 0
hdmi_drive=1

This is about all the configurations that this needs now.
I'll try contacting the seller and ask if this is a software problem.
If not, I guess I'll just buy one again, as I already soldered to it, and I doubt I'll get any refunds lol