Monday Dec 31, 2012

Creating a Portable Java/JavaFX Rig using the Raspberry Pi

So you're a mobile/embedded Java developer who just can't get enough time with your devices? Need to get your JDK/JavaFX ARM fix on the go? It's easy and inexpensive to do just that with only a few essential parts:

  • Raspberry Pi
  • Atrix Lapdock, which provides portable keyboard/video/mouse and power for the Raspberry Pi!
  • A few cables and adapters (shown in videos, described in linked article below)
  • SD card (8G or more, Class 6 or higher)
  • Edimax EW-7811Un wi-fi adapter

That's all the hardware you'll need to make some serious, very portable ARM Java magic. Total cost was under $120 when I started this adventure; YMMV.  :-)

There are a few differences between setting up the soft-float (SF) and hard-float (HF) versions of Raspbian, but this recent post covers the basics of getting an OS on the SD card for booting and configuring the Pi. The two key differences between SF and HF configuration to this point:

  1. Overclocking. HF Raspbian allows for easy overclocking from the raspi-config utility. A word of warning, though: The OS devs caution that the maximum overclocking setting has been known to corrupt SD cards, and I've found this to be the case several times. Stepping down one level to the next-to-fastest overclocking setting works a treat.
  2. Wi-fi configuration. SF Debian/Raspbian wi-fi configuration can be best accomplished using the instructions in the aforementioned post. Trying the same thing in HF Raspbian results in a message suggesting the use of the wi-fi graphical configuration tool...and it's even easier. With the Edimax, all I did was boot with both ethernet cable & Edimax connected, sudo su, startx, and run wpa_gui under the Internet menu (WiFi Config on the desktop if not root). Fill in your wi-fi details (I used WPA2/CCMP for my WAP) and then File|Save Configuration when finished. Quick, easy, and done.  :-)

Below are links to a couple of short video tours of my mobile Java/JavaFX "testing rig". I'd embed them directly if the Roller blog software supported it (if someone knows how, please let me know!). After the video links is a link to an article/video I used as a template when I originally made mine. Great stuff, fun, and extremely useful...for me, anyway. Hope you enjoy it!

Video 1: Intro to Raspberry Pi & Atrix Lapdock, Part 1 of 2
Video 2: Follow-on to Raspberry Pi & Atrix Lapdock, Part 2 of 2

Reference article/video

Happy hardware hacking,
Mark

Sunday Nov 25, 2012

Prepping the Raspberry Pi for Java Excellence (part 1)

I've only recently been able to begin working seriously with my first Raspberry Pi, received months ago but hastily shelved in preparation for JavaOne. The Raspberry Pi and other diminutive computing platforms offer a glimpse of the potential of what is often referred to as the embedded space, the "Internet of Things" (IoT), or Machine to Machine (M2M) computing.

I have a few different configurations I want to use for multiple Raspberry Pis, but for each of them, I'll need to perform the following common steps to prepare them for their various tasks:

  • Load an OS onto an SD card
  • Get the Pi connected to the network
  • Load a JDK

I've been very happy to see good friend and JFXtras teammate Gerrit Grunwald document how to do these things on his blog (link to article here - check it out!), but I ran into some issues configuring wi-fi that caused me some needless grief. Not knowing if any of the pitfalls were caused by my slightly-older version of the Pi and not being able to find anything specific online to help me get past it, I kept chipping away at it until I broke through. The purpose of this post is to (hopefully) help someone else recognize the same issues if/when they encounter them and work past them quickly.

There is a great resource page here that covers several ways to get the OS on an SD card, but here is what I did (on a Mac):

  • Plug SD card into reader on/in Mac
  • Format it (FAT32)
  • Unmount it (diskutil unmountDisk diskn, where n is the disk number representing the SD card)
  • Transfer the disk image for Debian to the SD card (dd if=2012-08-08-wheezy-armel.img of=/dev/diskn bs=1m)
  • Eject the card from the Mac (diskutil eject diskn)

There are other ways, but this is fairly quick and painless, especially after you do it several times. Yes, I had to do that dance repeatedly (minus formatting) due to the wi-fi issues, as it kept killing the ability of the Pi to boot. You should be able to dramatically reduce the number of OS loads you do, though, if you do a few things with regard to your wi-fi.

Firstly, I strongly recommend you purchase the Edimax EW-7811Un wi-fi adapter. This adapter/chipset has been proven with the Raspberry Pi, it's tiny, and it's cheap. Avoid unnecessary aggravation and buy this one!

Secondly, visit this page for a script and instructions regarding how to configure your new wi-fi adapter with your Pi. Here is the rub, though: there is a missing step. At least there was for my combination of Pi version, OS version, and uncanny gift of timing and luck. :-)

Here is the sequence of steps I used to make the magic happen:

  • Plug your newly-minted SD card (with OS) into your Pi and connect a network cable (for internet connectivity)
  • Boot your Pi. On the first boot, do the following things:
    • Opt to have it use all space on the SD card (will require a reboot eventually)
    • Disable overscan
    • Set your timezone
    • Enable the ssh server
    • Update raspi-config
  • Reboot your Pi. This will reconfigure the SD to use all space (see above).
  • After you log in (UID: pi, password: raspberry), upgrade your OS. This was the missing step for me that put a merciful end to the repeated SD card re-imaging and made the wi-fi configuration trivial. To do so, just type sudo apt-get upgrade and give it several minutes to complete. Pour yourself a cup of coffee and congratulate yourself on the time you've just saved.  ;-)
  • With the OS upgrade finished, now you can follow Mr. Engman's directions (to the letter, please see link above), download his script, and let it work its magic. One aside: I plugged the little power-sipping Edimax directly into the Pi and it worked perfectly. No powered hub needed, at least in my configuration.

To recap, that OS upgrade (at least at this point, with this combination of OS/drivers/Pi version) is absolutely essential for a smooth experience. Miss that step, and you're in for hours of "fun". Save yourself!

I'll pick up next time with more of the Java side of the RasPi configuration, but as they say, you have to cross the moat to get into the castle. Hopefully, this will help you do just that. Until next time!

All the best,
Mark

About

The Java Jungle addresses topics from mobile to enterprise Java, tech news to techniques, and anything even remotely related. The goal is to help us all do our work better with Java, however we use it.

Your Java Jungle guide is Mark Heckler, an Oracle Java/Middleware/Core Engineer with development experience in numerous environments. Mark's current work pursuits and passions all revolve around Java and leave little time to blog or tweet - but somehow, he finds time to do both anyway.

Mark lives with his very understanding wife, three kids, and dog in the St. Louis, MO area.



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