Using a Raspberry Pi as an Information Radiator

February 28, 2013 Laurence Koret

We have found the Raspberry Pi to be a cost-effective replacement for the Mac minis that we use in our office to drive TVs that are information radiators. We use these radiators to display the build status of our ci (continuous integration) projects. At ~$60 (Raspberry Pi, USB WiFi, enclosure), it’s 90% cheaper than using a $600 Mac mini.

Ordering

  • Raspberry Pi Model B Revision 2.0 (512MB). We ordered from Amazon even though they charged a healthy premium ($47 vs. $35). We did not want to wait 12 weeks for the unit to arrive (they are still notoriously backordered).
  • SB Raspberry Pi Case This case protects from static and bumping. It looks cheap and is not sturdy. With more time we would have bought this one from Adafruit
  • USB wifi adapter
  • 32 GB SD card A 4 GB card would be adequate, but we already had this one in our server room.
  • Power adapter Again found in our server room. Cheap USB cables may not work with Raspberry Pi, at least that was the experience of one of my co-workers. The USB cable that comes with this power adapter works. I wanted to make sure the same thing did not happen to me as this was also mentioned on Tech Crunch. My working voltage was 5.022 Volts with a multimeter. From the same article they recommend a voltage of 4.75 and 5.25 volts and “anything outside this range indicates that you have a problem with your power supply or your power cable.”
  • HDMI cable Another server room find.

Setup The Raspberry Pi is different from a home PC/Mac: It doesn’t have a built in hard drive or flash memory chip; it has an SD card for a brain.

  • First, you need to get an operating system for it. The best place for this is: Raspberry Pi.org. The one I selected is the Raspbian “wheezy”
  • I used the instructions found here to setup the SD on my Mac laptop.

Once the operating system was installed I booted the Pi with an HDMI monitor connected. You will be presented with a screen as seen here from Adafruit. This is named, appropriately enough, the Raspi – config screen. Here I selected a few of the different options:

  • change_locale and change_timezone
  • ssh which enables ssh
  • boot_behavior – start desktop at boot
  • expand_rootfs

After rebooting, I inserted the USB wifi dongle. This brought an antenna icon right on the desktop, double-clicking this brought up a menu which let me enter the credentials I needed to access the wireless network.

After completing the wireless install I setup from the Raspi – config screen:

  • update – this upgrades the software on the Raspberry Pi to the latest version

To boot the Raspberry Pi to specific webpage at boot follow these instructions:

Boot to browser

Accessing your Raspberry Pi without a keyboard or mouse attached

Our Raspberry Pi’s are connected to TVs with no keyboard or mouse attached; however, we needed to access the console remotely. Our solution? We used x11vnc combined with a VNC client so that we could access them remotely.

The following VNC clients will work:

Apple’s Screen Sharing will not work; it is unable to attach to a passwordless VNC server.

Do the following to install x11vnc which will allow you to VNC into a “headless” (no monitor, keyboard, or mouse connected) Pi from an external machine. Install true-type fonts for your viewing pleasure.

sudo apt-get install ttf-mscorefonts-installer

sudo apt-get install x11vnc

sudo curl -o /etc/init.d/x11vnc https://raw.github.com/starlightmedia/bin/master/x11vnc

sudo chmod 755 /etc/init.d/x11vnc

sudo update-rc.d x11vnc defaults

Here is the finished project:

Raspberry Pi working on my desk

About the Author

Biography

More Content by Laurence Koret
Previous
Retail App Showdown: Consumers Rate Top 100 U.S. Retailers' Apps on iOS and Android
Retail App Showdown: Consumers Rate Top 100 U.S. Retailers' Apps on iOS and Android

Xtreme Labs has released a report about how the top 100 U.S. retailers fare in the mobile space. The list o...

Next
Continuous Integration to Cloud Foundry.com Using Jenkins in the Cloud
Continuous Integration to Cloud Foundry.com Using Jenkins in the Cloud

Continuous integration using Jenkins is increasingly seen as an effective tool for reducing the cycle time ...