OpenCpn Install on Android Tablets Easier Now.

[Ptizef]

Hello

I read somewhere that Ubuntu is about to launch a smart phone and tablet version
of it's OS
Does that means O will work on these devise ?
JP

[armido]

Ptizef,

See: http://www.cruisersforum.com/forums/...nes-95400.html

The only reason any flavour of linux running as the primary operating system on an arm device would not allow OpenCPN or other open source software program to be installed, is if the system is altered to prevent it. Such a move would be diabolical. An insult to the spirit and design of linux. But, where profit is the motive anything can be built around the linux kernel - take android for example - as long as programs remain free or coders only receive "donations". The downside of android is the total loss of security and privacy for the user. Devices running android are sophisticated tracking tools. A boon to marketers and anybody who writes a "free" program capable of stealing your personal information. Will Canonical follow android's example? We can only hope the answer is no, because it would destroy a powerful reason for using linux - security.

armido

[armido]

mrm,

I missed your post until now. Your idea makes sense. Since a linux browser running in a chrooted environment is able to connect to the internet - it seems entirely reasonable that a gps should be able to communicate data to a navigation program like OpenCPN through a network socket.

There is an .apk called "slick usb 2 serial" that apparently connects serial devices to android. What may be required to bridge the divide between the android connection and a chrooted linux is a mystery to me. I'll see if it is possible to enquire with the apk's author about doing this.

In the meanwhile, if there is anybody skilled in writing android apps who understands the problem and may be able to produce a solution - we're all ears.

armido

[mrm]

armido, I started to dig a bit deeper and there are some good and some bad news.

The good news first:

• there is a method addNmeaListener in LocationManager class, which gives Android applications a direct access to the NMEA stream from device's GPS;
• the low level Java serverSocket class is available, as well as are Threads.

So writing a TCP server providing NMEA on a socket appears to be trivial, but, bad news:

Android environment was designed to forbid programmers (using Android SDK) from creating persistent background daemons, as Android insists on being able to kill any app at any time for memory/resource management. There seem to be two ways to mitigate/circumvent this limitation. One is to ensure a highest possible priority for server app process by registering a (foreground) service. Another is to program using NDK (native apps) but (as far as I was able to understand) installation of such an app requires a rooted device and not sure about access to NMEA data from NDK apps.

I have too much work to dive even deeper, so I hope that some experienced Android developer will chime in.

Marius

[armido]

Marius,

The requirement a device be rooted is not a problem - since devices must be rooted in order to install linux and OpenCPN anyway. I'm going to pass this by a sailor/nerd friend who is a programmer. If he can't help maybe he knows somebody who can.

armido

[dave777]

Originally Posted by mrm

Given the above assumptions are true, the solution I propose is to write a small Android native server app (daemon), which will bind to a TCP/IP interface (on Android side) and serve NMEA stream to any app which can connect to it. Once such service is up and running, OpenCPN may be able to connect to it directly.

Only an idea, maybe helpful, maybe rubbish...

That was a great idea ... until I just checked on the OpenCPN online manual and read:

Full Network input and output, including TCP, UDP, and GPSD services.

Now it's an outstanding idea. Looks like it no work needed on the OpenCPN side, just an Android side generic (re)transmission of the GPS data from the API. This little utility could help many Linux gps apps too, not just OpenCPN.

[armido]

Dave777, mrm,

Dave, where'd you grab the quote in your last post. mrm's proposal to write an android server application? I don't see it anywhere in this thread. Anyway, mrm - if you do there a lot of sailors who will be grateful for your contribution!

Thanks,
armido

[armido]

O.K.,

I just went back to mrm's first post in this thread. His proposal preceded revelation in his subsequent post he is too busy right now.

However, a friend of mine may be working on this now.

armido

[mrm]

Originally Posted by armido

O.K.,

I just went back to mrm's first post in this thread. His proposal preceded revelation in his subsequent post he is too busy right now.

However, a friend of mine may be working on this now.

armido

Well... I kind of found a welcome change of focus from current workload in this small coding project. Couldn't spend much time on it so it is *far* from being finished, but I would like to ask everyone who is interested to do a little testing.

Here is the app: http://infinity.eti.pg.gda.pl/tmp/NMEATest.apk

At the moment the only functionality is as follows:
- if device's GPS is switched off, application will patiently wait;
- if the GPS is on, first 200 NMEA sentences received will be displayed, then the app will stop;
- minimum Android version supported is 2.3.3, API 10.

All testers: please report if it works for you as described or not and include the device make/model and Android version in your feedback.
TIA

Marius

[armido]

mrm,

Is the test for built in, external or both gps types? I have my built in gps on and nothing registers in your test. Xoom UMTS, 3g euro running xda JB 4.2.1 nightly build 124.

Thanks for you continued participation in this thread!

armido

[mrm]

It is for built in GPS.

I target minimum 2.3.3 (API 10).

I tested on physical device HTC Desire S, 2.3.5. Also got it running in emulator at 4.0 (API 14) and 4.2 (API 17) (however without actual NMEA, as emulator support for this feature is buggy).

How far did you get? Did the app display anything? Was GPS on?

Can you try on original vendor installed image? Googling suggests, that Cyanogen derived images have problems with NMEA. May be well true for other images based on stock Android. Seems that vendors are patching NMEA support themselves, but do not give back...

[mrm]

Got a 'working OK' report from two friends. One with SE Xperia X10, other with Samsung Galaxy. One variance observed was that on Xperia NMEA sentences started to arrive only after GPS got an actual fix, while on Galaxy sentences started to flow immediately after GPS was switched on.

I have just checked server logs. There were 16 unique downloads so far but almost no reports. Why?

[oem]

Originally Posted by mrm

I have just checked server logs. There were 16 unique downloads so far but almost no reports. Why?

I might be among the downloaders. I'm sorry, but my time to test is limited. And I only possess and old HTC Desire (the original) with very limited memory, so I didn't try to test it at all.

I still do think this thread is among the most interesting for some time :-) A backdoor to Opencpn on Android.

[mrm]

Thanks for feedback, oem. The app package is about 160kB. When installed it is 640k at the moment. But I understand time constraints very well

A friend of mine tested on a recent Nexus 7 with 'OK, it works' report.

Will try to continue coding when I get some free time.

Marius

[Roel Smidt]

Originally Posted by mrm

Got a 'working OK' report from two friends. One with SE Xperia X10, other with Samsung Galaxy. One variance observed was that on Xperia NMEA sentences started to arrive only after GPS got an actual fix, while on Galaxy sentences started to flow immediately after GPS was switched on.

I have just checked server logs. There were 16 unique downloads so far but almost no reports. Why?

Hi Marius,

Just tried it and works fine on my Samsung Galaxy Tab 7.7 (GT-P6800). My tab has a built-in GPS, is rooted and runs Android 4.0.4.

I normally use OziExplorer for Android on this tab but would love to get OCPN running with my Dutch S-57 ENC's.

Greetings from the Netherlands,
Roel