Kobo Aura refresh rate?

[Martin Gregorie]

Does anybody who is using a Kobo eBook reader to run XCSoar measured its
screen refresh rate? If so, I'm curious to know whether it can match the
usual XCSoar full screen refresh rate of 1 per sec on a WM/WinCE-based
PNA?


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[David Hirst]

I used a Kobo Mini and XCSoar last season. Its refresh rate is about the same as a PNA but slower than an Android phone. What is 'distinctive' about the e-ink screen is the ghosting you get - there is always a slight shadow of the previous image on the screen. Over time, with enough refreshes, this may disappear but sometimes it's necessary to skip to a (largely white) menu and back just to clear the ghosting. Not ideal but the sunlight readability more than makes up for it.
I've made up a few Kobo Mini / XCSoar /GPS bundles and also found that the screen quality, in terms of its ability to hold high-contrast text without refreshing, is quite variable. I'm hoping that this will improve with further production volumes or bigger screens. Such are the joys of early adoption.

[Paul Crabb]

I've used the Kobo mini for over a year with Xcsoar, it is very readable in the cockpit in all lighting conditions and any ghosting that happens does not cause any readability issues... I don't notice it when flying. I have put a second kobo on the panel dedicated to airspace watching and final gliding... another whopping £40 down the drain :). I'm really impressed with Xcsoar on the kobo - even more impressed when I found out how to get GPS and power into the USB port with Xcsoar 6.8 beta

Paul Crabb

[7C]

On Saturday, 20 June 2015 01:18:02 UTC+1, Martin Gregorie wrote:

> Does anybody who is using a Kobo eBook reader to run XCSoar measured its
> screen refresh rate? If so, I'm curious to know whether it can match the
> usual XCSoar full screen refresh rate of 1 per sec on a WM/WinCE-based
> PNA?
>

Refresh rate isn't really relevant - XCSoar only updates the screen at 1Hz (to match the GPS feed) and all the e-inks can update at about 3Hz or higher.

The only time you notice the display being slower is on menus. But then the processor (at least on the Mini) is faster than all the WinCE devices I've seen which makes up for a lot of that!

Mel

[Martin Gregorie]

On Sun, 21 Jun 2015 02:40:35 -0700, 7C wrote:

> On Saturday, 20 June 2015 01:18:02 UTC+1, Martin Gregorie wrote:
>> Does anybody who is using a Kobo eBook reader to run XCSoar measured
>> its screen refresh rate? If so, I'm curious to know whether it can
>> match the usual XCSoar full screen refresh rate of 1 per sec on a
>> WM/WinCE-based PNA?
>>
>>
> Refresh rate isn't really relevant - XCSoar only updates the screen at
> 1Hz (to match the GPS feed) and all the e-inks can update at about 3Hz
> or higher.
>

There are some, otherwise attractive, ePaper displays that aren't that
fast, (3000 full screen refreshes/hour, 1200 mS/refresh) but that, with a
partial area refresh could squeak in under the second. I wanted to know
if the Kobo also needed to use this sort of trick. Since asking, I've
been sent a link to a video showing that it can do a full-screen refresh
in 500mS or less.

[Papa3]

A somewhat related question - has anyone run into problems with a Kobo (Kobo Mini) washing out in direct sunlight due to overheating? I flew with one for the first time in a club glider earlier this month running TopHat on a Kobo Mini. The Kobo was secured via a suction mount to the canopy. I liked it quite a bit, until the display began to become fainter and fainter. At some point, the touch screen became unresponsive. Luckily, I had a backup copy running on my HTC One which worked fine.

Some Googling suggests that some Kobo Minis may have issues with long periods in direct sunlight. Anyone in the gliding community care to comment?

P3

[fenog...@yahoo.com]

I have been using a Kobo Mini with XCSoar for the last two years, and have never had a wash out problem. My wife also uses the same mini as a e-reader at the beach. She sits in direct sun light by the hour, and has not reported any issue.

I find the "ghosting" to be a non-issue in flight. After years of using a PDA I'm just happy I can see the numbers in all flight conditions. And, the entire system was great value for money, less than $100 (in a 40 year old glider).

Gary

[simon.t...@gmail.com]

That's quite feasible. The stated max operating temperature of E-ink displays is low (50C). If you've got no air circulating in the cockpit and the sunlight's shining at right angles to the display, ghosting and eventually fading is possible. High ambient temperatures are less significant, but certainly won't help.

Briefly opening a vent to get some airflow over the display should resolve the problem temporarily, or tilting the display so that the sun's shining at a more oblique angle. Using a Kobo Mini with a white casing and even avoiding using the 'inverse' colour scheme (black infoboxes) might have some effect too.

[Johan Pretorius]

I tried using my Samsung Galaxy S2 to do this job in a club glider (once) and was immediately convinced that I need a different solution. I've looked at using a Kobo for the e-Ink display and battery life, but couldn't think of how to get GPS connected... Can someone (Paul, Gary?) please point me in the right direction? On the internet I found some information from a guy who got all the way to getting XCSoar running in simulator mode because he hadn't connected GPS input.

Also, would you recommend using a Kobo mini or Kobo Touch? I know I wouldn't go for a Kobo Glow, because the backlight is a waste of energy in the cockpit. But compared to the Mini, the Touch has a nice big screen.

[Papa3]

I recently flew with the TopHat branch of XCSoar on a Kobo mini. The GPS source was a hockey-puck connected through a "Y" USB cable. Here's an example:

http://tophatsoaring.org/Kobo.html

If I didn't already have a ClearNav in my racing glider and I was looking for a low-cost solution, I would go with TopHat hands-down over other options I've flown with. It's very much optimized for XC/Racing and has a lot less "stuff" going on. I was up and running from scratch after watching 1 or 2 tutorials and spending 10 minutes with someone who has flown with it. Really pretty slick.

My son and I also loaded TopHat on two Android devices (an HTC One and a Samsung Galaxy S5), so we had 3 versions running in the glider (Grob). I thought it was more than adequate on the S5-less so on the HTC One. With the phone in Airplane mode and an external USB battery, we had a pretty nice, self-contained Nav and logging unit.

Erik Mann
P3

On Monday, June 22, 2015 at 3:37:32 PM UTC-4, Johan Pretorius wrote:
> On Sunday, June 21, 2015 at 9:51:22 PM UTC+2, simon.t...@gmail.com wrote:
> > On Sunday, June 21, 2015 at 2:56:42 PM UTC+1, Papa3 wrote:
> > > A somewhat related question - has anyone run into problems with a Kobo (Kobo Mini) washing out in direct sunlight due to overheating? I flew with one for the first time in a club glider earlier this month running TopHat on a Kobo Mini. The Kobo was secured via a suction mount to the canopy. I liked it quite a bit, until the display began to become fainter and fainter. At some point, the touch screen became unresponsive. Luckily, I had a backup copy running on my HTC One which worked fine.
> > >
> > > Some Googling suggests that some Kobo Minis may have issues with long periods in direct sunlight. Anyone in the gliding community care to comment?
> > >
> > > P3
> >

> I tried using my Samsung Galaxy S2 to do this job in a club glider (once) and was immediately convinced that I need a different solution. I've looked at using a Kobo for the e-Ink display and battery life, but couldn't think of how to get GPS connected... Can someone (Paul, Gary?) please point me in the right direction? O
> >
>

[David Hirst]

> I've looked at using a Kobo for the e-Ink display and battery life, but couldn't think of how to get GPS connected...

If you're handy with a soldering iron, the Kobo has a (low-voltage i.e. 3.3V, NOT 5V or RS232) serial port that you can get at. See this thread:
http://www.mobileread.com/forums/showthread.php?t=204786

or this:
http://blueflyvario.blogspot.co.nz/2014/04/blueflyvariottl-integration-with-kobo.html

Once you have access to the serial port, you have a lot more options like driving a 3.3V GPS module (Ebay) directly, talking to a Garmin using a RS232-to-LV Serial module (Sparkfun), or even an HC-05 Bluetooth module (also Ebay) to talk to a Nano for example.

Happy hacking
David

[fenog...@yahoo.com]

This might have been a low battery problem rather than a screen heat issue. If the battery is at it's end the Kobo will screen freeze and nothing works after that.

Gary

[Papa3]

Nope - battery at 90+ percent. Like I said, the Googlesphere suggests that some versions (maybe early production) of Kobo were prone to washing out and becoming unresponsive in direct sunlight. FWIW, a highly sophisticated heat shield (i.e. a piece of cardboard box taped over the Kobo) seems to have eliminated the problem.

P3

[7C]

> > This might have been a low battery problem rather than a screen heat issue. If the battery is at it's end the Kobo will screen freeze and nothing works after that.

I've had problems with the screen locking - the touch screen is infrared sensor and I think sometimes the sun triggers it to believe a long touch on the screen has happened. Holding my finger on the screen for a few seconds will unlock it again. When this happens a little lock symbol is displayed.

Mel

[Paul Crabb]

I've had screen locking occur from time to time - I got round it by opening up the rear case and drilling a small hole in the rear cover directly over the reset button hole ( visible when the rear cover is removed ) - I then put a cut down drawing pin through the holes with a bit of sticky tape over it. In flight I can now give the drawing pin a "squeeze" which does a "reset" on the kobo.

I'll try the finger hold on the screen :)

The only thing I miss on the kobo is an audible airspace warning. the airspace cross section view in xcsoar is very effective.

Papa3 link to tophat gives the best details for setting up to use power and gps data through the USB port.

Paul.

[sergioala...@gmail.com]

Hi, for those of you that used Kobo Mini, what GPS do you suggest and how difficult is to connect to Kobo?
Thank you in advance,
Sergio

[Johan Pretorius]

Sergio I haven't yet had a Kobo to try this on but my best information points to this plan:

. Run XCSoar on a Kobo. Set it up to receive GPS data by TCP over a wifi link. I've tested this so I know XCSoar can do it.
. Run an app called BlueNMEA on my Samsung Galaxy S2. This apparently lets you output GPS signal over wifi. I haven't tested this part.
. Have a portable battery available in the cockpit to charge the S2 (or the Kobo) via usb if it runs out of power... though I'm expecting it to last at least 2 hours because the screen can stay off.

[Johan Pretorius]

Oh also... I plan to test this on the the ground first as I've had problems in the past with radio interference from setups like this (specifically with the USB charging). If someone who knows about such things can tell us all how best to avoid that problem, I for one would be grateful.

[PBA]

I'm a diehard Kobo/top hat fan.
If you haven't used an ereader screen in a glider, you are in for a treat.

I just replaced my first kobo (left other in rental car :( )
and my new (old stock) kobo has the sunlight issue. It's becoming very light during the flight to almost unreadable. This is especially bad with high temperatures. I did not have this problem with my previous kobo so I think this is a QC issue.

I have my kobo wired (soldered) to a colibri II. This is an amazing setup that gives you everything you need from a moving map + IGC approval for badge/comp/record flying. The kobo charges the colibri and the whole unit is charged from a micro USB.

I have noticed the radio inference if I hold this unit close to my Dittel radio, doesn't effect it unless I hold it close though so it's a non issue for the most part.

[Papa3]

Glad I wasn't the only one with the sunlight issue. I've built a temporary shade out of black cardboard. I'll test this out a few more times before claiming victory, but it seemed to help a lot in the two flights where I used the prototype version (i.e. the top of a box taped to the mount with wing tape).

[Charlie M. (UH & 002 owner/pilot)]

> Glad I wasn't the only one with the sunlight issue. I've built a temporary shade out of black cardboard. I'll test this out a few more times before claiming victory, but it seemed to help a lot in the two flights where I used the prototype version (i.e. the top of a box taped to the mount with wing tape).

Try "white/silver", better to reflect sunlight. If need be, pick which color on which side of the shield........

Hope it does not work out, so I can help out VS in the GC...... LOL........ (jk)....