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2.13" Monochrome E-Ink Bonnet Faded
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2.13" Monochrome E-Ink Bonnet Faded

by csotzing on Tue Jul 27, 2021 1:20 pm

I've built a temperature & humidity monitor out of a Pi Zero and a 2.13" Monochrome E-Ink Bonnet. After a few months of running 24/7 the display is not nearly as "dark" as it was; that is, the blacks are faded considerably. The application refreshes the screen every 5 minutes so I'm definitely not *over-refreshing. Can the contrast be configured or is this bonnet just wearing out?
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Re: 2.13" Monochrome E-Ink Bonnet Faded

by franklin97355 on Tue Jul 27, 2021 3:09 pm

Do you see any "ghost image"?

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by csotzing on Tue Jul 27, 2021 4:30 pm

Do you mean when the display inverts when it refreshes? In that case yes and actually having just watched the refresh a few times the black in the inverted image is *way darker, probably as dark as it ever was. It goes faded gray immediately after the refresh.

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by adafruit2 on Wed Jul 28, 2021 4:08 pm

yeah it could be wearing out, how many refreshes have you done (total count?) - we can ask if theres a refresh limit from the manufacturer

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by csotzing on Thu Jul 29, 2021 8:56 am

The display updates every 5 minutes and runs 24h. So for the time I've had it (plus the development cycles) I guess it's around 20,000 refreshes?

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by adafruit2 on Thu Jul 29, 2021 3:25 pm

yah that sounds... high. eink displays like these are designed for store labels, updating once a day
it could be that there's a max number of refreshes before it dims - oled's are the same!
we'll ask

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by csotzing on Fri Jul 30, 2021 2:53 pm

Thanks, I'd be interested to know if there a max number of refreshes. FWIW the example code includes a weather application which surely wouldn't be super useful if it only updated once a day!

Are there other display bonnets for a Pi Zero that include a Qwiic/STEMMA QT connector that you could recommend for a (somewhat) frequent refresh?

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by adafruit2 on Fri Jul 30, 2021 3:01 pm

once a day weather is pretty useful! the magtag does that and we have it on our fridge :)
https://learn.adafruit.com/magtag-weather

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by csotzing on Tue Aug 03, 2021 10:30 am

Any update on max refreshes? Perhaps there is a way to adjust the contrast as the board ages? Thanks for your help.

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by adafruit2 on Wed Aug 04, 2021 2:57 pm

hiya they replied asking if the display was exposed to sunlight?

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by csotzing on Wed Aug 04, 2021 3:04 pm

The device is mounted to a wall that never gets direct sunlight. It's actually quite dark in that room.

The fact that at refresh the fully blacked out screen is very dark is still odd to me. The bonnet is still capable of that kind of contrast so perhaps the fade is a configuration issue?

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by adafruit2 on Wed Aug 04, 2021 3:09 pm

what if you display all black

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by csotzing on Thu Aug 05, 2021 9:17 am

Wow I'm actually kind of surprised the result of that test. Drawing a black rectangle that fills the screen *is the correct contrast, very black. But when I go back to my text display it fades out as it was previously. I'm not setting anything except the fill (no contrast, etc.). And to reiterate the text printed in really crisp black letters originally and no code has changed since I wrote it a few months ago.

Exampe code excerpt for text:

Code: Select all | TOGGLE FULL SIZE
# Draw the humidity text
draw.text(
   (x_offset, (calib_display_height/4)-(humidity_text_height/2)+y_offset),
   self._humidity_text,
   font=self.large_font,
   fill=BLACK,
   )


Example code for the box:
Code: Select all | TOGGLE FULL SIZE
       
#black box
shape = [(0,0), (calib_display_width, calib_display_height)]
draw.rectangle(shape, fill=BLACK)


Thanks for all the help, much appreicated.

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by adafruit2 on Fri Aug 06, 2021 2:17 pm

could be you wore out the ink in those spots, could try flashing the whole thing black or white often to help reset it. we dont have any lower level insight - its just speculation

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Re: 2.13" Monochrome E-Ink Bonnet Faded

by csotzing on Sun Aug 08, 2021 11:33 am

I set the screen to all black and had it reset every 5 minutes for 24 hours. The black full screen was fully black (no fading). I then reverted it to the temp/humidity display and the text is faded again.

This tells me that it's not the pixels that are worn out because they displayed correctly as part of a fully blacked out screen.

Any word from the manufacturer?

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