e-Ink and other paper like displays

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I have periodically reviewed the e-Ink market looking for usable products w
ithout a lot of experimentation.  Most of what I find are displays without  
driver boards, a few high priced combos of displays with separate driver bo
ards, but few docs and very few displays an driver boards with some sort of
 docs and/or library support.  The one thing that always seems to be missin
g is an easy to find and easy to read document describing exactly what they
 will do and what they won't do.  Mostly the docs are a couple of poorly ma
de videos with no real explanation.  

I saw one video (don't recall the vendor or site) showing a display with pa
rtial updates such as would be needed for a display of a real time device s
uch as a... ventilator for example.  That looks promising.  But the display
 is monochrome and I still didn't find any docs on exactly how it would be  
interfaced to a system.  

My main interest in them is to provide a display optimally viewable in any  
lighting.  

There seems to be more than one manufacturer of these displays.  When they  
are sold by third parties (mostly through Aliexpress) it is hard to tell wh
ich brand of display they are.  If I understand correctly one company owns  
the patents with multiple manufacturers licensing.  

All of the inexpensive displays are pretty tiny.  One maker includes touch  
screens even on 1.5 inch displays!  My finger tip is not much smaller than  
that.  The prices rise rapidly with size.  A 4 inch display is pushing $40.
  

Anyone used any of these displays?  Anyone happy with these displays?  Tips
?  Cautions?  

--  

  Rick C.

  - Get 1,000 miles of free Supercharging
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Re: e-Ink and other paper like displays
On 20/05/2020 02:35, Rick C wrote:
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I have only seen them on a couple of evaluation boards - I haven't had  
use of them myself.

The advantages of them are very low power, high resolution (if you want,  
and pay for it), and readability in sunlight.  But they are /slow/.  
They are often too slow for "real time devices" - if you use e-ink for a  
digital clock, for example, it will feel sluggish on the seconds digits.

For good viewing in a wide range of lighting, also look at OLED  
displays.  These can be very nice, high resolution, full colour, and  
give more brightness for the power than backlit LEDs.  But no display  
technology is ideal for /all/ lighting conditions - there will always be  
some compromise.

Really, to test the display in different lighting, there is no  
substitute to getting some demo boards and looking at them.


Re: e-Ink and other paper like displays
On Wednesday, May 20, 2020 at 2:48:38 AM UTC-4, David Brown wrote:
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ts without a lot of experimentation.  Most of what I find are displays with
out driver boards, a few high priced combos of displays with separate drive
r boards, but few docs and very few displays an driver boards with some sor
t of docs and/or library support.  The one thing that always seems to be mi
ssing is an easy to find and easy to read document describing exactly what  
they will do and what they won't do.  Mostly the docs are a couple of poorl
y made videos with no real explanation.
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h partial updates such as would be needed for a display of a real time devi
ce such as a... ventilator for example.  That looks promising.  But the dis
play is monochrome and I still didn't find any docs on exactly how it would
 be interfaced to a system.
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any lighting.
hey are sold by third parties (mostly through Aliexpress) it is hard to tel
l which brand of display they are.  If I understand correctly one company o
wns the patents with multiple manufacturers licensing.
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uch screens even on 1.5 inch displays!  My finger tip is not much smaller t
han that.  The prices rise rapidly with size.  A 4 inch display is pushing  
$40.
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Tips?  Cautions?
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I recently saw a video of a display updating a value once per second.  That
's not a problem unless you want to update the entire screen.  They've had  
partial update for a while now.  The three color displays are very slow req
uiring many passes and many seconds to update the display.  


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It is not required to be highly visible in the dark.  Just like paper exter
nal light is required for eInk.  Even so, I recently saw front lighted disp
lays listed somewhere.  


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I don't need to do a look test on e-paper.  It works.  What I am looking fo
r info on is how to drive them from an MCU.  It used to be that a separate  
driver board was used since there are a few voltages that are required and  
some other details I don't fully understand.  This time around I see the di
splays from Adafruit which seem to combine that interface with the display.
  They aren't really commercial units though.  They clearly gave no thought
 to how they might be mounted and I think they have components on the same  
side of the board as the display, or that may have been another company.  
  

It's kind of weird that there is very little structure to the market.  When
 you buy an MCU board they give lots of details and you know exactly who ma
de each part and where to get good info on using it all.  The eInk display  
products come from multiple display producers and they are not all the same
 at all.  None of them provide very good support or documentation.  

I remember once contacting one of the display makers asking for more detail
s on building an interface for their units.  They just told me all the info
rmation was in the data sheet and that I should buy the controller boards.  
  

--  

  Rick C.

  + Get 1,000 miles of free Supercharging
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Re: e-Ink and other paper like displays
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As well as the strange negative voltages they need very specific timings to
drive the internal elements.  Those timings are usually secret and
proprietary to the display, and possibly damage it if you get them wrong.

You would need a CPLD or FPGA to act as a timing converter (TCON), but you
can't build one because the timings are not published.  Presumably Adafruit,
Waveshare and friends have them under NDA and wrap them up in an easier
package, but they're you're stuck with their PCB design.

The most standardised interface I've seen is the e-reader SoCs (eg
iMX6SoloLite) which have a dedicated EPD controller.  There is usually a
firmware blob that provides the timing information - it is possible to
download the firmware for an e-reader and extract the blob, but then you're
on your own.

Waveshare are one of the better sources of providing interface modules and
info, by the way:
https://www.waveshare.com/product/displays/e-paper.htm
https://www.waveshare.com/wiki/Main_Page#OLEDs_.2F_LCDs

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If you're Amazon building the next Kindle, you can get the info.  They
aren't interested in selling one-offs.

Theo

Re: e-Ink and other paper like displays
On 21/05/2020 09:44, Rick C wrote:
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I guess the technology has moved forward.

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Front-lighting may be okay, but I think it would often be hard to get  
the angles right for an even lighting.  Generally, e-Ink needs an  
external light source - if that's okay for the application, then great.

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Fair enough.  I'm afraid I can't be any help there - I haven't used them  
myself, and anything I could look up, you can look up too (and probably  
have).  My general advice if the manufacturers are not giving good  
information would be to ask your favourite distributors for suggestions  
and data, but I expect you've thought of that already too!  (And I am  
aware that the quality and helpfulness of distributors and FAE's varies  
a lot from country to country.  We have several very good ones, but not  
everyone is that lucky.)

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I've found Adafruit to be a useful source for one-off devices, such as  
screens to fit with rpi's for test benches, but not for larger numbers  
of units or for when you need to do a lot of work to use the devices.

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I suspect that most e-Ink customers are huge - they can talk directly to  
the manufacturers, rather than having to use publicly available information.

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Re: e-Ink and other paper like displays

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Not as a developer, but I own a Kindle. Both contrast and readability are  
great, but refresh time is very slow compared to other technologies. Cool  
temperatures seem to increase this time even more. You also have traces of  
previously shown picture unless you do a full erase / redraw (which  
decreases refresh time even more).

If you want a display readable in varying conditions, maybe think of a VFD  
instead?

--  

https://www.youtube.com/watch?v=9lSzL1DqQn0


Re: e-Ink and other paper like displays
On Thursday, May 21, 2020 at 9:45:09 AM UTC-4, Queequeg wrote:
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We discussed displays the other day and I mentioned the VFD as an option, b
ut there seems to be some preference for an LCD.  I think there would be mo
re interest in the eInk if people were more familiar with them.  Your exper
ience with the Kindle was probably some time ago.  Displays are faster now  
and smaller units are faster still, then partial display updates are even f
aster yet.  

--  

  Rick C.

  -- Get 1,000 miles of free Supercharging
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Re: e-Ink and other paper like displays
On Tuesday, May 19, 2020 at 8:35:44 PM UTC-4, Rick C wrote:
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I run a moving map program on a Kobo Glo (a nice Linux box, ~$50 on eBay).
Some ghosting, but real-time updates of the map are quite acceptable.
Fabulous screen outdoors in bright sunlight (this is in my plane).

The controller is a very complicated beast and not like LCD.
An OEM module may not have adequate update rate for some applications.

Interesting stuff!
Best Regards, Dave

Re: e-Ink and other paper like displays
On Friday, May 22, 2020 at 6:11:58 PM UTC-4, Dave Nadler wrote:
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We may have talked about this before.  When you say "plane" do you mean a glider?  I have a faint recollection of talking to someone who used an e-Ink display in a very tight cockpit in a glider.  

--  

  Rick C.

  -+ Get 1,000 miles of free Supercharging
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Re: e-Ink and other paper like displays
On Friday, May 22, 2020 at 8:16:08 PM UTC-4, Rick C wrote:
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Yup, here's a short movie: http://www.nadler.com/sn10/20160423_SN10_to_TopHat_in_ArcusM.MOV

Re: e-Ink and other paper like displays
On Saturday, May 23, 2020 at 9:18:16 AM UTC-4, Dave Nadler wrote:
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Your cockpit shows exactly why I prefer the eInk display.  It is more like the mechanical displays in visibility.  The LCD display in the SN10B is much less visible.  

I'm starting to think I need to get my hands on some hardware.  

--  

  Rick C.

  +- Get 1,000 miles of free Supercharging
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Re: e-Ink and other paper like displays
On Saturday, May 23, 2020 at 3:29:38 PM UTC-4, Rick C wrote:
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The SN10 LCD is transflective and sensitive to angle of view.
In the video, SN10 is actually higher contrast than the eInk display.
We encourage installation towards the top of the panel to improve contrast.

Always trade-offs.
Let us know how you make out with the eInk display,
Best Regards, Dave

PS: That video was taken of my former ArcusM cockpit a few years back.
I and the airforce cadet in the back seat bailed out of my ArcusM in 2018.

https://www.youtube.com/watch?v=v8I3A3dqsu0

Please do not try this at home.

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