leJOS and Lego Mindstorms EV3

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Re: leJOS and Lego Mindstorms EV3

Postby Aswin » Thu Sep 05, 2013 7:18 am

Hi Andy,

Yesterday I had a first shot at running Lejos on EV3. I'm not yet there.
I wondered for what reason I had to install Linux. I suspect this is because one cannot create a linux partition on the SD card from windows. Is this the reason?
My NXT blog: http://nxttime.wordpress.com/
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Re: leJOS and Lego Mindstorms EV3

Postby gloomyandy » Thu Sep 05, 2013 7:41 am

Lots of reasons to use Linux, mainly because that is what Lego used to develop the EV3 code (not surprising given that it runs Linux!). It may be possible to do all of this on Windows or MacOS but it is much easier using Linux. I'm sure at some point we will be able to make this work on other OSs but it will certainly take some work! But yes one of the things that is tricky to do on Windows is to create the various Linux style partitions.

I have a lot of changes for the EV3 version that I hope to check in over the next few days, so you may want to hold off making any code changes until then. Lots of fixes and a lot of changes on sensor side of things.

Andy
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Re: leJOS and Lego Mindstorms EV3

Postby msx » Thu Sep 05, 2013 8:49 am

Hello there, new to the board and Mindstorm :)
I'm looking forward to use lejos, the official development environment have been the biggest disappointment with EV3. I think it's huge, slow, bloated and the graphical programming environment is hard to read and mantain. Being an hardcore java developer, i'm all with lejos :)
I'll try the current software asap, but i have a question before: does running Lejos makes the mindstorm official firmware unavaiable? Or does the brick returns to his normal behaviour when i remove the SD-card? That's becouse i have just purchased the set and i'd like to experiment more with official programs before eventually removing support for official system :)

Thanks, now i'm off to read the wiki! Hopefully i'll be able to help a little with the project too.
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Re: leJOS and Lego Mindstorms EV3

Postby gloomyandy » Thu Sep 05, 2013 9:28 am

Yep removing the SD card puts things back as they were.
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Re: leJOS and Lego Mindstorms EV3

Postby robotChicken » Thu Sep 05, 2013 4:03 pm

Thanks for all the hard work getting lejos running on ev3. Amazing job.

I followed the wiki instructions, and I got everything working and tested.

I did this on fedora 18 in virtual box and only had one issue. Eclipse couldn't find /usr/share/java/jna-3.2.7.jar. Fedora installed jna.3.0-4 and named it jan.jar. Since I don't use eclipse much I wasn't sure how to change the build path/linking. If anyone could point me in the right direction that would be great. In the interim I created a symlink /usr/share/jna-3.2.7.jar to jna.jar, and now it works fine.

My interest in robot programming is mostly in getting robots to work together. I would like to get my new ev3 connected over bluetooth to my old nxt. Can you point me in the right direction?

I would also like to try connecting the ev3 via tcpip to a host computer for mapping and graphing. Are there libraries in the ev3classes for that type of thing. Again, any information you could give would be helpful.

Thanks again.
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Re: leJOS and Lego Mindstorms EV3

Postby gloomyandy » Thu Sep 05, 2013 4:14 pm

Sorry I've not started looking at Bluetooth yet. If you have the SD card up and running then I assume you also have WiFi running to it? If so then you have TCP all ready to go. You should be able to use the standard Java network classes to talk to your PC. One of the big gains of the EV3 is that we have pretty much full Java and Linux so many of the things should just work (or at least work with a little effort).

As to the JNA stuff I think that what you have should work. You can change the jar files you link with by right clicking on the ev3classes project and choosing properties, in there should be an entry called something build path and the JNA libs should be an external jar.

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Re: leJOS and Lego Mindstorms EV3

Postby robotChicken » Thu Sep 05, 2013 4:32 pm

Andy,

I do have wifi set up. I didn't realize I could just use standard java, although I should have known. I'll give it a try. Thanks.
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Re: leJOS and Lego Mindstorms EV3

Postby dendrobates » Tue Sep 10, 2013 7:29 am

Hello, my name is Beat and I'm completely new in mindstorms programming. For my degree I have to a bachelor thesis. And I wanted to do something with mindstorms. The thesis I do, is a robot that can drive autonomous through a track. With every round a neuronal network tries to improve the driving skills. For this the robot has four IR-sensors that measures the distance to the walls of the track and two touch sensors for register the collision with the walls. For time measurement I use a colorsensor. Every time the robot passes for an example a red line, the time will start from new. I would like to do this with EV3. Would it be possible to develop this robot with the actual software or should I buy a NTX? Is there an overview which classes I can use? Thanks a lot for your reply.
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Re: leJOS and Lego Mindstorms EV3

Postby superj » Mon Sep 23, 2013 7:50 pm

Hi,

I am very new to both EV3 and leJOS, having received my EV3 set last week... I am trying to install leJOS as per instructions here (http://sourceforge.net/p/lejos/wiki/Cre ... SD%20card/) however when I try to boot using the SD card, EV3 seems to freeze on the Mindstorms logo screen (LEDs switched on) and nothing happens.

When running the update script, I get this output:

....checking.sdcard
....erasing.sdcard
rm: cannot remove ‘/run/media/joel/LMS2012/*’: No such file or directory
....copying.kernel.to.sdcard
....copying.filesystem.to.sdcard
....copying.application.to.sdcard
....copying.extra.modules.to.sdcard
....force.depmod.on.first.boot
....copying.lejos.to.sdcard
.... Java
.... Jna
sudo: dpkg-deb: command not found
.... libffi
sudo: dpkg-deb: command not found
....writing.to.sdcard

REMOVE sdcard

Any help would be greatly appreciated. I am running Fedora 19 on a Dell Inspirion N3010

Many thanks,
J.
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Re: leJOS and Lego Mindstorms EV3

Postby skoehler » Mon Sep 23, 2013 8:07 pm

It's probably because dpkg-deb is not found. Which distribution are you running?
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Re: leJOS and Lego Mindstorms EV3

Postby gloomyandy » Mon Sep 23, 2013 9:09 pm

It looks like you are trying to create the SD card using 0.2.0. Is there a reason why you are not using the latest version? Later versions do not use dpkg-deb when updating the sd card.

Andy
PS Please note that none of this has been tested using Fedora as a development system.
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Re: leJOS and Lego Mindstorms EV3

Postby superj » Tue Sep 24, 2013 6:47 pm

Thanks everyone for your feedback..

I downloaded v. 0.4.0 and whilst I didnt get any errors this time round, leJOS still doesnt boot.

Should I try with a different distro? Which one do you recommend please?

J.
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Re: leJOS and Lego Mindstorms EV3

Postby gloomyandy » Tue Sep 24, 2013 11:28 pm

How do you know it has not booted? If may be trying to talk to your WiFi network. Do you have a WiFi dongle plugged in? Which one? What happens if you take it out? If it shows the leJOS splash screen without the dongle then that almost certainly means that you have not correctly setup the wpa_supplicant.conf file (you did configure that didn't you).
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Re: leJOS and Lego Mindstorms EV3

Postby superj » Wed Sep 25, 2013 8:54 am

I "know" it hasnt booted because the screen just shows the Mindstorms logo and red LEDs switched on and stays like that. WiFi dongle is plugged in - I am using the Edimax EW-7811Un. wpa_supplicant file configured as per instructions. TBH I haven't tried booting without the dongle. I will try that tonight and report back. Many thanks for all your help!!!!
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Re: leJOS and Lego Mindstorms EV3

Postby gloomyandy » Wed Sep 25, 2013 1:51 pm

Red LEds and no screen change does not mean it has not booted. It almost certainly means there is a problem with your network setup. What sort of network are you trying to connect to? What type of security settings? Does the WiFi dongle flash at all?

You could try connecting to the EV3 via USB. remove the WiFi dongle, plug in a USB cable. Once booted try pinging 10.0.1.1 if that works try ssh to 10.0.1.1.
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