4.41 inch ePaper Display for the rPi

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There are a number of displays on the market for the Pi.  I need one  
that will work over a wide temperature range.  I would like to use an  
ePaper display, but there is very limited selection currently.  Between  
the size needed and the temperature range I find no existing ePaper  
product that will work.

I have found a couple of Kickstarter projects that seem to use the  
Aurora type of ePaper display which meets the temperature requirement,  
but they are only for the smaller displays, the largest being 2.7 inches  
I believe.  These controllers are not compatible with the larger size  
displays.

I have also found 4.3 inch displays in a different ePaper technology  
which won't meet the temperature requirements.

I am thinking about making a Pi oriented controller board for the 4.41  
inch size display.  The resolution is 400x300.  There is a controller  
chip that is promoted for the larger displays, but I haven't found  
documents explaining what it does.  I actually can't find any documents  
on exactly how to drive the larger displays other than using the eval  
controller module which uses the controller chip.  So clearly it will be  
a long row to hoe to try to get the info and design a board.

In essence, the difference between this display and others out there is  
the temperature range and the fact that the display size is not limited  
by the rPi size.  I'm wondering how much interest there might be in such  
a product if I make it.

--  

Rick

Re: 4.41 inch ePaper Display for the rPi
On Thu, 18 Jun 2015 11:42:27 -0400, rickman wrote:

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Are any of these displays coloured ePaper? What about touch screen  
capabilities?  The 4.4" size  sounds useful for what I'd need: a display  
with low power consumption that is easily readable in direct sunlight.  
The space limitation is because that's as big as I can use in my glider  
without hiding other instruments. Touch screen would suit me better than  
a separate controller. I'd only need single touch.

I'm currently using a Medion S3747 with a transreflective screen. This  
remains readable in direct sunlight though its contrast does tend to  
reduce in very bright conditions. ePaper would be better despite its  
relatively low refresh rate. The software I run is available for both WM  
5/6 and Linux, so should work well any RPi.
  

--  
martin@   | Martin Gregorie
gregorie. | Essex, UK
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Re: 4.41 inch ePaper Display for the rPi
On 6/18/2015 6:39 PM, Martin Gregorie wrote:
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One thing to keep in mind is that ePaper is only low power when you  
aren't changing the display.  When you *are* changing the display it is  
*very* slow compared to any other technology *and* not remotely low  
power.  For low power stick with LCD reflective.

How often does the display need to be updated?  I haven't been looking  
hard at ePaper for awhile.  Back a couple of years ago there was a  
dearth of info on the displays.  More recently I am finding a bit more  
info on the displays and how to use them.  Somewhere in my travels I  
think I found one manufacturer of a display unit that included a touch  
screen and even illumination LEDs (they have to be front lighted rather  
than back lighted).  If I come across it again I will make a note of it  
for you.

My app needs to be protected from the weather, so no touch screen.  I  
wonder if a capacitive touch sensor can be placed below a piece of  
glass?  But I'm sure it would need to be thin and so fragile.  They use  
gorilla glass for cell phones I believe.  They do a hot dunk in  
potassium salts which displace sodium atoms on the surface with  
potassium.   Being larger this puts strain on the two surfaces which  
make it very hard.  There may be a decent product there, but it would be  
a sizable investment to get started with unknown payout.


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Transflective is the poor compromise between reflective and  
transmissive, marginally usable in either light or dark but excelling in  
neither.  I think the transflective works best with indoor lighting...  
of the right type.  You could use a reflective display with a front  
light when dark.

I think you can roll your own touch screen.  It just lays on top of the  
display.  Can you find any that would fit?


I had a phone conversation with Pervasive today.  I am not the only one  
who is not crazy about the way ePaper is marketed.  It has always been  
short on detailed info.  I think they are mostly targeting the "large"  
users and just don't put much into the public info.  No one has said  
anything about an NDA yet, so I guess that is not the issue.  This  
conversation seemed to show interest on their side.

The current product is a panel from Pervasive with a controller board  
from Mpicosys.  Mpicosys rolled their own chip which may be a hard  
version of an FPGA.  I can't imagine anyone investing the bucks for an  
ASIC, but maybe.  I was told when they produced it the result was better  
than the Pervasive chip so Pervasive dropped their chip.  However, they  
are designing a new chip which will work better and will be incorporated  
in their new 4 inch display.   So it will eliminate one board from a  
system.

He said the new Pervasive chip is not compatible with exiting displays  
because it must be incorporated into the display.  I'm guessing the new  
controller included some of the circuitry that is currently included on  
the display.  The docs for the smaller displays refer to loading the  
image into memory before giving the command to display it, so there must  
be a chip with memory and the actual timing logic on board.  The 4.41  
inch and larger displays are a bit different, but they still have an SPI  
type interface, so clearly there is some sort of a digital device other  
than simple drivers.  Maybe I'll know more when I get the info.  I wish  
I could figure out why they hold back so much.

--  

Rick

Re: 4.41 inch ePaper Display for the rPi
On Thu, 18 Jun 2015 19:20:47 -0400, rickman wrote:

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I don't think that's a problem - ever seen the power a standard PNA burns  
with the brightness full up for outdoor use?

I just looked back at my records and see the PNA that was I measured  
power consumption used 320 mA - I don't know whether that was a Binatone  
B.350 or the Medion S3747 that I use now, but subjectively they have  
similar brightness indoors. FWIW the avionics draw is 483 mA for two  
varios, my FLARM and the PNA running LK8000. By comparison the ATR500  
airband radio draws 200mA when its listening (1100 mA transmitting) and  
my mechanical T&B draws 500mA. All currents measured at the 12V inlet to  
the panel.  

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The principal limit is the GPS subsystem in the PNA - that updates once a  
second, so that's the fundamental refresh rate for the display as a  
whole. If the EPaper display refreshed once every 50mS that would be good  
enough for navigation etc, and possibly even fast enough during  
interactions such as selecting a new destination, etc.
  
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I doubt I'd need the extra LEDs since we never fly gliders at night.

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For my use case the transreflective display is never worse than a  
standard PNA such as the Binatone B.350 and usually is far more readable,  
but then I am talking about use under a fully transparent bubble canopy  
and with a certain amount of illumination coming off my shirt etc as well  
as directly from the sun.
  
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I haven't looked yet, since the Medion is doing an acceptable job so far,  
but I realise that virtually all PNAs were WM/WinCE based and new ones  
are almost non-existent now M$ pulled the plug on those OSen. So, I'm  
keeping a listening watch to see what would be available if my Medion  
dies.

I had noticed that comparable TFT displays are available for the RPi but  
wasn't aware that you could get small ePaper - hence my interest.
  
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Certainly sounds interesting. Thanks for the heads-up.


--  
martin@   | Martin Gregorie
gregorie. | Essex, UK
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Re: 4.41 inch ePaper Display for the rPi
On 6/18/2015 8:13 PM, Martin Gregorie wrote:
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I don't know what a PNA is.


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Then that is a problem.  At room temperature the display refresh takes  
about a second and slows considerably as temps drop.  This is the  
extended temperature version I'm referring to.  Maybe the standard temp  
version updates a bit faster, but 50 ms is totally out.

The standard temp version does have a partial update capability which  
might help with refresh of just the data and not the entire display.

Yeah, these things are nothing like conventional displays.


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I wish I knew what a PNA is.   I assume it is nothing like PDA...?


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Would a 2.7 inch display be ok?  That is out there now with FOSS.  Check  
out repaper.org.

BTW, I found that display with the touch panel.  6" diagonal and 600x800  
resolution, 0?~50?.  Refresh time is also about a second.

http://www.good-display.com/products_detail/&productId30%2.html

Here is a link for the smaller display eval board.

http://www.pervasivedisplays.com/kits/ext_kit


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I think this industry is under capitalized.  I can't think of any other  
reason why it is so hard to get info and why they seem to be slow to  
bring new products to market.  After thinking about it a bit I realize  
they probably rolled their timing controller for the larger displays in  
an FPGA because of limited funds and got a minimum implementation.  A  
third party did a chip design of some sort that worked a lot better.  
Still, this is only good for them, but why did someone else need to do  
it?  Now they have their new chip but it is only forward compatible with  
new product.  I guess it is still early days in the industry.

Too bad I couldn't have been involved with them sooner when they were  
doing the FPGA design.  I can rock FPGAs, especially the low power ones!

--  

Rick

Re: 4.41 inch ePaper Display for the rPi
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If this is an application where you can roll your own CPU board, it may be
worth looking at the SoCs used in e-readers.  For example, the Kindle
Voyage uses a Freescale MCIMX6L8DVN10AB from the iMX6 family, which includes
onboard e-paper support.  If not roll your own board, perhaps there is a dev
board you can use?

It would seem that the niche where you want HDMI or RGBHV into a separate
e-paper driver chip is pretty small (and such would be inefficient burning
power for sending unchanging video) so it makes sense to have the controller
integrated onto the SoC.

Theo

Re: 4.41 inch ePaper Display for the rPi
On 6/19/2015 6:01 AM, Theo Markettos wrote:
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I think using a big MCU chip to drive a low power display over an SPI  
port is a bit of overkill.  These displays come in families and I have  
only found one family of ePaper displays that work over an extended  
temperature range.  The larger displays in this family have exactly one  
display controller (board and chip) and that is provided by a third  
party, resold by the display maker.  Oddly enough it seems the  
controller chip is not rated for the same temperature range as the  
display.  So although they have an extended temperature range display,  
there is no extended temperature range controller for it!

I'm going to use the lack of an extended temperature range controller  
(board or chip) as a lever to get the spec for the display and maybe I  
can roll my own in an FPGA.

I'm not sure why you are talking about HDMI or RGBHV.  These are purely  
black and white displays, not even gray scale.  They are not refreshed  
on a regular basis, only updated when needed and take about a second to  
redraw the screen.

--  

Rick

Re: 4.41 inch ePaper Display for the rPi
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You didn't say the panel spoke SPI.  Is this it:
http://www.pervasivedisplays.com/LiteratureRetrieve.aspx?ID21%4528
I'm a little unsure why it speaks SPI but also needs a timing controller
(TCon) as well.  Does the display need refresh (like traditional hsync/vsync
timing) with the SPI just being state changes, or are they more closely
related?  Could you run the SPI from the CPU and the timing from a
CPLD/FPGA?

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That's probably a useful strategy.

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Since we're on the RPi group, most people are going to assume you're wanting
to show the Pi display on the e-paper panel, which means HDMI-to-something
conversion.  If it's as SPI then it's just a peripheral, so nothing
particularly Pi-specific here, except perhaps in terms of code to drive it.

Theo

Re: 4.41 inch ePaper Display for the rPi
On 6/19/2015 3:27 PM, Theo Markettos wrote:
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Yes, that is the extended temperature version of the panel.  The  
standard temperature model is ET044AS013, doc 1P038-00.  Very similar  
specs other than the temperature.  But the standard temp model can have  
partial updates and another feature I can't recall at the moment.  The  
docs suck in some ways.  It can be hard to find info at times.  Best to  
memorize everything once you find it, lol.


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That is the $64,000 question, how do the interfaces work?

The smaller units (2.7 inches and smaller) have an SPI interface and  
some discrete controls.  The larger displays are "more complicated"  
according to the rep.  I guess the interface is complex enough that they  
just don't want to give out the specs so they don't have to support that  
level of user.

There is no timing like a video signal because this is *not* video.  The  
data sheet describes the operation as, display is powered up, data is  
sent, the display updates and power is removed.  I expect the power  
up/down is optional, but you get the point.  Only the Ents would be able  
to watch "video" on this display.


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I'm getting rather weary of trying to pull teeth.  If this go around  
doesn't get an info, I will have to give up on ePaper.


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HDMI ain't happening.  No need whatsoever and much difficulty.   I don't  
see how an HDMI interface on a display would be at all rPi specific.  
Lots of pies have LCD or LED text displays.  This is a similar interface  
but supports graphics.

Now that I recognized Pervasive doesn't have a wide temperature  
controller, I also realize they are asleep at the switch.  ePaper  
displays have always been hard to get info on.  That still has not  
changed.  If you think Pervasive is hard to get info from, try getting  
good info from Good Displays, a purely Asian company.

--  

Rick

Re: 4.41 inch ePaper Display for the rPi
On Thu, 18 Jun 2015 21:25:15 -0400, rickman wrote:

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Sorry: PNA = Personal Navigation Assistant

This which covers portable/pocketable devices ranging from something like  
a Garmin GPS II+ or eTrex (simple walking or cycling GPS) to devices with  
moving maps like the Binatone B.350, MioPocket, (advanced hiking GPS,  
portable satnavs for cars, etc).

They tend to get specialised programs installed for less-common uses,  
e.g. my Medion came with both road navigation and trekking programs in  
ROM but I run the LK8000 glider navigation program off an SD-microcard.
  
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How fast could it manage a full-screen refresh? 2Hz should be OK provided  
that it can update displayed text fast enough to handle data entry  
through menu selection or via an on-screen keyboard (single key at a  
time).  
    
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Its really just a PDA with built-in GPS receiver. I thought PDA was a  
well-known term or I'd not have used it.

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Its a bit small - both the PNAs I've been using have 3.5" displays.  
Here's a shot of mine doing its thing while sitting in a tree in my  
garden. It gives a reasonable idea of the sort of display I like:

http://www.gregorie.org/gliding/pna/

All the zeros being shown are because the device is stationary at ground  
level and, because it has been stationary since it was switched on, it  
doesn't yet know what direction is north.
  
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The partial update video makes it look as if the display might be fast  
enough, but there's one odd omission - nowhere does it quote the screen  
resolution in pixels.

The typical 3.5" PNA display is 320 x 240 pixels which, as you can see  
above, gives an adequate display. Any less probably wouldn't be much use.  

I notice that the Embedded Artists 2.7" display (the one Pervasive is  
using) is only 264x176 and bi-colour, so would not be high enough res for  
what I want. Pity, as its contrast is good and it looks easy to connect  
to an RPi.


--  
martin@   | Martin Gregorie
gregorie. | Essex, UK
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Re: 4.41 inch ePaper Display for the rPi
On 6/19/2015 7:38 AM, Martin Gregorie wrote:
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Not even a 1 Hz update rate.  I checked the spec and it takes 1.4  
seconds to update the display at room temperature and during that time  
the display is flashing from image to reverse image to image.  They  
write a negative image to minimize ghosting.

If you need 1 second GPS updates, the ePaper display is not the right  
way to go.


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I get a bit tired of people using specialized technical jargon here when  
they don't know who they are talking to.  Sometimes it is hard to find  
the meaning in a google search if you don't have an idea.  After I made  
the post I googled PNA and it showed up in the first hit as Personal  
Navigation Assistant.  So obviously it is fairly common even if I didn't  
know it.  I guess I should have searched first, lol.


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I'm familiar with navigation units, I've just always called them GPS  
units or even just GPS.  I don't quite understand.  Why would you want  
to duplicate this display and how would you expect to get this on an  
external display?


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The Pervasive 4.41 inch display is 400x300 (both temperature ranges) and  



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When you say "bi-colour", you mean black and white, right?

--  

Rick

Re: 4.41 inch ePaper Display for the rPi
On Fri, 19 Jun 2015 13:12:28 -0400, rickman wrote:

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Fair enough. It's just that some people are running this type of  
navigation application on Kobo eReaders and are reporting good results.  
Is thr Kobo refresh noticeably faster than the Pervasive displays and  
their controllers?
  
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We tend to reserve this term for the 'traditional' Garmins and so-called  
'blind GPS' or 'GPS puck' such as the Garmin GPS35 or GPS18.

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I'm looking at the possibilities of running one of the OSS glider  
navigation programs on an RPi with a small TFT or ePaper display. That  
would work well. I have plenty of space behind the panel for the RPi and  
its display would go where the PDA is mounted at present.
    
Both the leading OSS programs, LK8000 and XCSoar have already been ported  
to Linux.

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So, using this with an RPi looks like a sensible way to go. I'll remember  
that.
  
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Yes. That's Embedded Artists term, not mine. The other reason, apart from  
better resolution for using the Pervasive 4.41 display is that it seems  
to offer four grey shades plus white, but is it fast enough to be worth  
consideration?


--  
martin@   | Martin Gregorie
gregorie. | Essex, UK
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Re: 4.41 inch ePaper Display for the rPi
On 6/19/2015 3:10 PM, Martin Gregorie wrote:
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I haven't seen a Kobo.  Is it ePaper?  Lots of readers are LCD these  
days, no different from a tablet.  The ePaper displays I have seen may  
be faster than 1 second update time, but not by a lot.  You watch the  
page get refreshed.  It is not at all unnoticeable.


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"Traditional"?  Does that mean a handheld GPS or a "pro" unit intended  
for flying?


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For $50 ball park you can get one of the smaller displays to test and  
see if you think it will work for you.  I don't know drivers are  
available that integrate it as a standard display.  Everything I've seen  
so far just lets you roll your own app to talk to it.


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I don't know.  I'm not sure you really need even a 1 Hz update for a GPS  
display.  Some time back when I was building a GPS product they were  
just coming out with modules that would update the coordinates at 4 Hz.  
  Until then the low cost devices were all updating at 1 Hz.  This data  
is basically 1 second old by the time the calcs are done and you receive  
it.  I can't imagine you need second resolution on a display with so few  
pixels.  Are you using this for velocity and altitude as well as mapping?

Bottom line is ePaper is not really real time unless you are a snail.  
The nature of ePaper is that it is slow to update and the low power  
aspect is only apparent when you aren't updating.  When it updates it  
uses a similar power level to the LED backlight of a small LCD display,  
~30 mA at 3.3 volts just for the display, not counting the controller.

--  

Rick

Re: 4.41 inch ePaper Display for the rPi
On Fri, 19 Jun 2015 15:34:11 -0400, rickman wrote:

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As far as I know it is, assuming I've gotten the name right. If it  
wasn't, people wouldn't be using it in their cockpit.  

Don't forget that, with the large amount of info crammed onto the display  
by clever use of colour, e.g. different types of airspace have different  
colours. My example shows two types. GRL under the glider symbol and BOUrn  
are ATZ (not to be entered unless you're landing there) are filled with  
grey diagonal lines. The plain grey arc on the right is a NOTAM  
(temporarily restricted airspace), but Control Zones and danger areas are  
differing colours of red.

Bottom line: colours are very useful, so giving them up for a monochrome  
display means that the latter must be very much easier to read under all  
conditions.

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A handheld unit. The non-mapping aviation GPS units tend to show  
analogue dial-like images plus digital values for each output because  
those are easier to read fast. They'll show speed, altitude and track  
(not heading: a GPS doesn't know where the plane is pointing, just the  
direction in which its going).

GPS units that can display maps appeared several years later than the  
'traditional' non-mapping units. I think there are two reasons for this:  
LCD displays large enough to show a usable map took their time arriving  
and so did big enough affordable non-volatile memory to store maps that  
covered enough country and were detailed enough to be useful.  
  
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That's about right. XCSoar, which I don't use, solved the problem by  
becoming an Android app, so by definition the stuff it needs (SD-cards,  
touch screens, sound, colour displays) are already there.

LK8000, which I prefer, is probably heading for the RPi but may also  
appear on Android.

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The only time I really notice the full screen update lag is when I'm  
climbing in a thermal, typically taking 15-30 seconds per turn. The  
display is far enough that its useless for rolling out on a heading when  
you leave the thermal: you use sun and landmarks instead and this way the  
display has caught up when you next look at it.

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Not as prime instruments. LK8000 shows other, but related stuff such as  
wind speed and direction, ground speed, distance to the next turn point  
and whether you're above or below glide path to get there. Sometimes that  
can be amusing: I remember rolling out of a climb over Bury St Edmunds at  
4500 ft with the system saying I had 150km to go into wind to Edgehill  
and that I was 49,000 feet too low to get there. Stupid instrument: I  
already knew I needed a few climbs along the way.

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Fair enough, but its high contrast in direct sunlight is also a useful  
feature. That contrast is one reason why very many LCD aviation  
instruments are still monochrome reflective rather than backlit (except  
at night), just as most mechanical instruments have white markings on a  
black background.

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Understood.


--  
martin@   | Martin Gregorie
gregorie. | Essex, UK
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Re: 4.41 inch ePaper Display for the rPi
On 6/19/2015 4:36 PM, Martin Gregorie wrote:
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I'm not really following you here.  Color is better than BW so the Kobo  
must be ePaper?

Why don't you ask the people who have the Kobo how fast it updates?


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Again, I'm not following.  If you have an Andriod app, how does that get  
an ePaper display?

When you say rPi, you mean Linux.  There is not really anything special  
about the rPi that I have been able to see.  I'm a rank novice with  
Linux but nearly everything I've learned about it applies equally to any  
Debian system.

In the system I'm looking at building I likely won't actually use the  
rPi as it is not rated over temperature, etc.  I'll likely end up using  
another board which has proper specs.  Not the Beagle board as the  
proprietor has indicated very emphatically that their boards are *not*  
to be used in commercial systems.  I guess I'll need to start looking  
for a decent alternative.


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You are talking about the lag in your GPS?  Yes, I've seen that with  
hand held units even while walking, lol.  To get real time updates... I  
mean truly real time, you need an inertial nav system.  Entirely  
possible with a simple G force sensor like they use in phones these  
days.  It requires some data fusion as the sensor won't be as accurate  
long term as the GPS, but over the short interval the sensor is faster  
to respond.


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If they are backlit that is called "transflective".  It's a partially  
mirrored back and is a compromise.  Like most compromises it makes  
everyone equally unhappy.  In this case it works in most lighting  
conditions, but not well.


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Ok, so for your app power is not really an issue.  Do you run from  
batteries or use a prop powered generator?  I've never seen any sort of  
prop on a glider (I live very near an airport so I do get to see a lot  
of them).  I just wondered if the weight of a generator would be less  
than the battery, but maybe you don't need a large battery so the weight  
just isn't an issue.

I know what you mean about the contrast of the ePaper display.  I have  
thought about designing a clock using one of the smaller displays.  
Unlike LCDs you can't find a decent ePaper clock display.  I'd have to  
use a graphic display and the power goes up significantly... I think.  
Like I keep saying, they aren't very good about releasing info.

Maybe I'll do the clock display just to get my feet wet.  I'm pretty  
sure the timing controller for the small ones is just an MCU.

--  

Rick

Re: 4.41 inch ePaper Display for the rPi
On Fri, 19 Jun 2015 17:35:10 -0400, rickman wrote:

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No, colour is generally better than monochrome, all other things being  
equal. But for outdoor use under an open sky a high contrast monochrome  
display is preferable given that any colour display apart from coloured  
ePaper is going to be washed out and hard to read, especially with direct  
sunlight on the display.

Thats no different from trying to use a viewfinderless camera outdoors on  
a sunny day, but you'll know that.

  
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Because there is nobody at my club who is using a Kobo. Question posted  
on rec.aviation.soaring
  
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It doesn't, but it does tend to get you a commercial device with standard  
standard APIs for accessing its colour display and touch screen, enough  
flash memory to install the app on and facilities for uploading maps etc  
and for downloading flight logs.
  
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Indeed, and it gets you a device that is small, light, not particularly  
hungry and cheap. As I said, I have a feeling that LK8000 has been ported  
to it, which would mean that somebody has added code to use SPI or I2C to  
handle small displays. It has to be them since we know there are no  
suitable HDMI displays and, although the el-cheapo Chinese back-up video  
displays accept a composite signal, the resolution looks to be  
unacceptably low.

The Beagle Board might also do the trick, but (so far) its not been  
mentioned as possible hw for LK8000.
  
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Some of the better varios are using 3D accelerometer arrays, but that's  
for gust sensing. Similarly, solid state blind flying panels are now  
common, good and quite cheap but lets not go there: they are for a rather  
different purpose.
  
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Batteries. Wind driven generators cause drag which stuffs glide  
performance. 12v systems are almost universal (Light aircraft use higher  
voltages). I carry a pair of 12v 7AH lead-acid batteries which can easily  
run my electronics for more than the longest day.

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Wander over one day, take a look and ask questions. Pilots are friendly  
and generally happy[*] to talk, answer questions and show you stuff

* just don't talk to a man who is in the middle of assembling and pre-
flighting a glider: he needs to concentrate on what he's doing.
  
Propellers: some gliders do have them because they carry auxiliary  
engines: if conditions deteriorate they can fire up and fly home rather  
than ending up in some farmer's field. Usually the engines and props are  
retracted behind the cockpit so you can't see them and come out on a  
pylon when needed, but nose-mounted, electrically driven folding props  
and small gas turbines are becoming popular. However, piston engines are  
still the most common, if the most problematic - because they add a huge  
amount of drag when extended, which is a big problem when it doesn't  
start. Thats why electric and jets are coming in: electric always starts  
and an extended jet adds very little drag even when not running.  

I fly a pure glider and usually winch launch rather than aero tow.
  
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Depends: at one extreme the Antares 20E is a 20m span electric self-
launcher with a pop-up 47 kW brushless motor and wings full of batteries.  
It has the power to take off and climb 10,000 ft. I have no idea what its  
batteries weigh. At the other end of the battery scale my pair of 7AH  
motorcycle batteries only add about 5 Kg to a glider with a normal flying  
weight of 280 Kg.  


--  
martin@   | Martin Gregorie
gregorie. | Essex, UK
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Re: 4.41 inch ePaper Display for the rPi
On 6/19/2015 7:22 PM, Martin Gregorie wrote:
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What does any of that have to do with the Kobo?


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Ok, so there is your device!


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When you find out let me know.  I'd be very interested in learning more  
about this app on the pi.


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I don't know it buys you much over the rPi.  It is a good board in many  
respects, but with the rPi 2, it's main advantage of a faster processor  
is gone.


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--  

Rick

Re: 4.41 inch ePaper Display for the rPi
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It's quite possible to get an Android device with an ePaper display, I
have one and it's pretty good at what it does.

Take a look at the Icarus readers, the E653 in particular.

--  
Chris Green


Re: 4.41 inch ePaper Display for the rPi
On 7/28/2015 10:02 AM, snipped-for-privacy@isbd.net wrote:
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How fast does it redraw the screen?

--  

Rick

Re: 4.41 inch ePaper Display for the rPi
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My guess would be somewhat less than 1 second though that's only
subjective.  It does produce some strange effects with standard
Android app animations but it mostly works pretty well.

--  
Chris Green


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