Fade image drawn on EPD

[PaulGoldschmidt]

Hey,

after some trial-and-error, I got the software up and running. The ESP (Waveshare EPD - ESP32 Driver board) catches all the weather data and communicates with the display, so it refreshes successfully. The only problem is now that the drawn image has very low contrast and the image is very fade overall (while refreshing, the display shows for a short while the image with full contrast, other projects are able to draw images and text with the full contrast).

Any idea how to solve this?

Kind regards, Paul

[G6EJD]

Have you tried the GxEPD2 example to ensure it’s not the driver? This is usually associated with the Busy connection being incorrect so that the display is not correctly drawn before drive is removed. Check the pin definitions for the Waveshare board are correct, I have a Waveshare board running without issues.

[G6EJD]

Which display are you using? Size?

[PaulGoldschmidt]

I'm using the 7.5 inch B/W 800x480 px (V2) EPD by Waveshare

[G6EJD]

And the code version?

[PaulGoldschmidt]

Everything should be up-to-date (using V16.11 for the Weather-Software)

[G6EJD]

And the T7 version?

[PaulGoldschmidt]

The newest one available (if you could tell me where to look up the version I will do it asap)

[G6EJD]

There are only two versions either the 7.5” or 7.5” T7

[PaulGoldschmidt]

Got it, it is the T7-Version.

[G6EJD]

Code works perfectly. I have just used the version here, compiled and uploaded to a Waveshare board connected to aT7 display, no problems found. Your doing something wrong. Most likely your display has been in direct sunlight and caused damage or it is too hot. This weather display uses exactly the same screen drawing as the EDP2 example.

[stefan-sherwood]

For others experiencing similar symptoms, I am experienced a similar problem, which I filed details on here. Using the Weather example here, this is what I am seeing. In real life it is quite faded, definitely looks better in the photo.

[SzymonSlupik]

Looks like it was damaged by strong sunlight. This happened to me once, but the display has recovered after about a day. Perhaps in your case the damage is permanent. I also had similar damage the other way around - dim background (see attached - the display on the left). They are fragile. Not sure why you can have an Amazon Kindle in full sunshine but not a Waveshare display though...

On Mon, Aug 23, 2021 at 9:37 PM stefan-sherwood @.***> wrote:

For others experiencing similar symptoms, I am experienced a similar problem, which I filed details on here https://github.com/Xinyuan-LilyGO/LilyGo-EPD47/issues/57. Using the Weather example here https://github.com/G6EJD/LilyGo-EPD-4-7-OWM-Weather-Display-1, this is what I am seeing. In real life it is quite faded, definitely looks better in the photo.

[image: image] https://user-images.githubusercontent.com/2094779/130508400-748e6f2c-c402-410b-9773-5f5d1252fa34.png

— You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub https://github.com/G6EJD/ESP32-e-Paper-Weather-Display/issues/153#issuecomment-904064690, or unsubscribe https://github.com/notifications/unsubscribe-auth/ADNT5PPZJP4OPL62JGJBWQDT6KPPNANCNFSM5BQRFCIQ . Triage notifications on the go with GitHub Mobile for iOS https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675 or Android https://play.google.com/store/apps/details?id=com.github.android&utm_campaign=notification-email .

[stefan-sherwood]

I don't think it has to do with sunlight. I took it out of the package it shipped in, never exposed it to sunlight. It was working perfectly when I plugged and unplugged it several times. Then I uploaded the software and it was immediately faded.

My purpose of posting this is not to reopen this report but to give other people with the same symptoms a link to follow.

[PaulGoldschmidt]

Had the same issue and mine works perfectly using other libs, I also pretty sure that the issue is not caused by errors in handling. Kind regards, Paul

[G6EJD]

I note the library was ‘updated’ in a bid to get a portrait mode, but it was not implemented correctly.

[stefan-sherwood]

Unfortunately the GxEPD2 library doesn't support the board I'm using. I will continue to look for another that might. Thanks.

[G6EJD]

You could go back a few versions on GitHub to the original version because that one worked.

[stefan-sherwood]

Happy to try that. Which project (GxEPD2 or LilyGo-EPD47) are you referring to?

[G6EJD]

LilyGo 4.7”

[stefan-sherwood]

I tried going back to 8 different past versions of LilyGo-EPD47 and they all produce the same low-contrast result. :(

It may be worth noting that when I try to fill the entire screen with black, looking close at the display I can see that not all of the dots are "on", as if it's trying to do grayscale.

[G6EJD]

If there was a fault I’d expect no display, or lines or section of black or no colour, the fact that it’s a grey scale image suggests the wrong colour is being selected, the driver that was first uploaded by LilyGo now some months ago, maybe 6 or more is a known working version.

Your display could be faulty, have you advised the supplier?

[stefan-sherwood]

I have advised the supplier and they said they're looking into it. I have about a week left on the return window so I'm hoping to determine one way or other whether or not it's a hardware problem. Because it worked until I uploaded the code I still have doubt it's hardware but who knows.

I tried many different versions of the LilyGo-EPD47 repository (including the first commit on Dec 1, 2020) and they all demonstrate the same problem.

[G6EJD]

Good luck