epaper instrument display

[StuartGunn]

Modern instrument displays are very visible but power-hungry. Older LED displays can be difficult to read in certain lights. I have often wondered why epaper is not used as it is so much easier to read. It can also be lit at night and we don't need colour at all.

I have started making an epaper cockpit instrument and it is working fine on the testbed, receiving data from another computer. At present it is based on an RPi zero and a 2.7 inch papirus screen, within a 3d-printed case. My immediate need is to display nmea wind and that is what I have done.

Screen update issues have been solved by using partial update and my instrument looks fine and updates quickly and seamlessly.

I am posting this to enquire whether anyone else is doing something similar or would like to cooperate with experience. I would certainly be interested in sourcing a slightly larger screen and one that does not have to piggy-back the RPi.

[Matt Johnson]

How fast can you update the screen? That is the only issue I could see with with them...what is the longevity of these screens? I've never had a kindle for longer than a few years since we update.

Matt

[autumnbreeze27]

what are you doing to let the user know the instrument is still updating?

do you have some kind of flashing pixel to indicate it's not locked up? In my experience when e-ink devices lock up the screen just stops updating. So you might think you're just really holding that course perfectly but the thing could be hung.

I've got an old nook I'd love to make a wireless instrument panel.

[LeaseOnLife]

interesting, subscribed!

[Paul L]

Doing anything in particular to protect from environmental issues? The eink panels seem sensitive.

(16) High temperature, high humidity, sunlight or fluorescent light may degrade the EPD
panel’s performance. Please do not expose the unprotected EPD panel to high
temperature, high humidity, sunlight, or fluorescent for long periods of time.

[StuartGunn]

Replying to all;
The screen updates at around 1 second frequency. It all depends on the frequency with which it receives new data.
My housing has an acrylic panel in front of the epaper screen and the housing is similar shape to Raymarine ST60 but in 2 halves with a rubber seal between. 2 waterproof buttons on the face for apparant/true and light.
I can fit a typical instrument cover over it when not in use.
I have had the instrument working continuously for over 24 hrs on test data and it has never frozen. I could easily add a flashing pixel. Another way would be to display wind speed with one decimal place as it never stays very constant. However, I won't do that unless I suspect there is a problem.
Kindles are regularly used for reading in strong sunlight. My wife has had her original one for years and it has not degraded at all despite using it in hot sunny weather (outside UK). In the UK high temperature is not a particular concern. The new displays are aimed largely at store labels. As they are relatively expensive they must be quite reliable.
I considered running it on wireless as I have a multiplexer on board (also RPi) which has wifi capability but as I have nmea wiring close to it there isn't any point.

Thanks for the comments but has anyone any advice on available displays?
Stuart

[Paul L]

Stuart
Sounds interesting. Can you post some pictures?

Thanks for the comments but has anyone any advice on available displays?

Pervasive seems to have a wide selection. Are these too expensive?

[StuartGunn]

Attached is a static photo. The display is in the first attempt at a housing, which is very rough but sufficient to prove dimensions and concept. The acrylic screen cover has not been stuck in and the screen will fit closer to the face of the housing in the final version. Also it still has its plastic sheet protector on.

Some crazing appears on the numbers, This is caused by ghosting during update. It isn't really obvious when running. The choice of font helps as it is rectilinear.

Top line is for Starboard/Port and Apparent/True.

I'll post a video of it running later. The inside looks untidy at the moment.

The display I am using is a Pervasive display which has been mounted on an RPi HAT to make the PaPiRus screen. Embedded Artists sell the same display with a more convenient driver board with fewer connetions. I didn't see that until I had made my first version and I would rather now wait until I can find a slightly larger screen at a reasonable price before investing further.. The problem with the Papirus HAT version is that it occupies the Rx GPIO pin of the RPi so that I can't transmit data through UART. It is annoying because the screen works with the pin disconnected but its software occupies the port. I have had to incorporate a USB/serial board to overcome that, which is a bit less tidy.

[StuartGunn]

The photo I attached didn't seem to attach. Here is an attempt at a video.

[StuartGunn]

One more try

[xslim]

I am actually developing something similar - using RPi as NMEA repeater over WiFi and Kindle Paperwhite to show the data in the web browser.
The one downside is that the browser works only in portrait mode.

[Paul L]

Originally Posted by xslim

I am actually developing something similar - using RPi as NMEA repeater over WiFi and Kindle Paperwhite to show the data in the web browser.
The one downside is that the browser works only in portrait mode.

Are you using a separate Paperwhite display or actually using a Kindle?

[ka4wja]

StuartGun, et al,
Since I wasn't sure what "epaper" referred to, I didn't see much to comment on...but, now I see you're referring to e-reader-type (Kindle, etc.) displays?
Yes??

But, wondering why you're referencing (comparing to) older LED displays (which were never designed for daylight viewing), as opposed to modern mono-chrome LCD instrument displays (which work wonderfully, even in direct sunlight), and are very power-stingy...

Originally Posted by StuartGunn

Modern instrument displays are very visible but power-hungry. Older LED displays can be difficult to read in certain lights. I have often wondered why epaper is not used as it is so much easier to read. It can also be lit at night and we don't need colour at all.

I assume you're looking for an open-architecture display??
How about one that accepts NMEA data of all types??

Although, I'm not very clear as to what you're actually trying to accomplish...here are some pics of my "modern" mono-chrome LCD displays....
Note that the ST-60+ Graphics (either side of the Wind display) are just displays, designed to display NMEA or "SeaTalk" data...







Not sure any of this is pertinent, but thought it might be...


Fair winds..

John

[xslim]

I use normal Kindle, it has Experimental browser (WebKit based). BTW, there is example page from SignalK / iKommunikatie project with using Kindle - check the docs / wiki on GitHub