April 1 Club Presentation Notes : What the Heck Is A Raspberry Pi ?

What The Heck Is a Raspberry Pi ?
by Scott Haley
KD5NJR
kd5njr@gmail.com

1.  Raspberry Pi is a single board microcomputer developed by the Raspberry Pi Foundation.

The main thrust of the foundation is to promote low-cost systems for the advancement of computer science education in Great Britian.  It’s small,

lightweight, cheap, now readily available and consumes much less power than a traditional PC.  The operating system is a version of the “free”

Debian Linux.  The cheap, small, low power aspects of the device lend itself not only to education, but to museums (for exhibit control) and

possible amateur radio operators.  For the ham, there are possibilities for this machine to be a fairly hassle-free additional computer for the

ham shack.  A lot of folks are keeping several “junker” machines around for digital modes, logging, APRS / Packet Internet Gateways (IGATES) ,

etc.

http://www.raspberrypi.org/about
2.  Technical Specs

$39.95 “Model B” with 512 MB RAM & LAN (Ethernet) port

https://www.adafruit.com/products/998

TBA : “Model A” without LAN port and 256 MB RAM
http://techcrunch.com/2013/03/26/pi-model-a-asia/

3.   What Do I Need ?

a. A RaspberryPi (and for safety’s sake, some kind of enclosure)
b. A USB Keyboard
c. A USB Mouse
d. A CAT-5 Cable to connect to your Ethernet Hub, or Ethernet Switch in the shack.
e. A mini-USB power supply (a.k.a. cell-phone charger) 5V, 700 mA
f. A SD card ( “class 10” ) about 8GB. <== Don’t skimp *
g. HDMI cable to your newer HDTV.  or analog cable to the spare TV. “RCA yellow” **
h. recommended : A USB Ethernet “dongle” ***
i. recommended : A USB “powered” hub ****
j. Temporary use of a computer with a SD memory slot *****

(see what you can dig up at Big Lots! or Tuesday Morning)

* I wasted a couple days horsing around with cheap microSD card in a SD card adapter.  Tony said this was meant for a cellphone and junk.
** Be sure you can mess around with the picture size and placement controls on the TV (in the back or in a menu)  You need to see the bottom of the screen to log in.  The true bottom of the screen might be obscured by the curved tube or plastic trim.
*** If you order one from Adafruit, likely the drivers will already be in Linux.
**** The RaspberryPi can’t drive too many USB loads.  So, it would be advisable to put your Wi-fi dongle, and other gadgets you might have that would consume power from the USB ports on a hub that plugs into the wall. 
***** YOu’ll use a real computer to write the operating system image to the SD card.  This is pretty easy on Mac and Linux machines. For

Windows machines, consider Berryboot.

4.  First things first
a.  Get your machine ordered.
b.  Locate your extra stuff in the junk bin.
c.  Find your power supply.  I’ve seen a lot of USB stuff in unexpected places (O’Reillys, Kum ‘n Go, checkout aisle at the grocery store etc.)
d.  Get your SD Card and card reader.  You might have this stuff already if you’ve got a digital camera.
e.  Browse the Quick Start Guide :  http://www.raspberrypi.org/quick-start-guide

5. The Operating System
There are a few versions of a few different operating systems for the RaspberryPi.  Wheezy is a popular one.  Start with it and see how you like

it.  To write the operating system onto the SD Card initially using a Windows PC, you’ll
a. download the RPi OS
b. download Win32DiskImager
c. use Win32DiskImager to write the OS to the card.

or, if you have your LAN near where you’ll be using your RPi at first, just use your Windows PC to copy BerryBoot to the SD card.

BerryBoot video :  http://w5drz.org/raspberrypi-part-2-berryboot/

6.  The First Boot Up
a.  Provided you have the OS image installed (or BerryBoot files copied over) hook up your Pi and continue with the Quick Start Guide.  Be

patient and log in when prompted.

OR

b.   Following the BerryBoot route, follow the prompts to let BerryBoot go to the Internet, get the OS, install it, and then define Wheezy as the

default OS.

From Wheezy’s command prompt, to gracefully exit, shutdown -h now , then pull power.

 

7.   The Next Boot(s)

Start working through the Adafruit tutorials.

a.   You’ll want to log into this thing remotely unless you want to hunch in-front of the TV all the time.  YOu’ll enable SSH on the RPi and

download, install, and run a SSH client on the PC of your choice.  I use the terminal in the Mac.  You could use Hyperterminal or PuTTY in the

Windows world.

Tutorial :  http://w5drz.org/raspberrypi-part-3-ssh/

b.   But sooner than later you’ll want to do something remotely that involves graphics, not just the command line.  You’ll need to install a VNC

server on the RPi and download, install and run a VNC Client on your other computer.  Yes, there are SSH and VNC apps for the iphone / tablet

crowd.

Tutorial :  http://w5drz.org/raspberrypi-part-4-vnc/

8.    Fun with the Graphical User Interface

9.    A Test Program in Python

a. write out your Python program in the text editor

b. run the Python interpreter

10.   GPredict <= nifty satellite tracking software

11.   More Ham Software

12.   Next Steps

The Web.
 For me, the web is pretty slow.  I’ll try to avoid surfing the net via VNC for sure.  And probably try to avoid surfing the net at all.   It’s doable, just slow.

Packet Radio
 With a USB to serial cable, it should be possible to interface the RPi to a TNC.  You could use a program like minicom to talk to the TNC and go from there.  KE7KUS is doing this with his Kenwood TM-D710.  http://www.4x4ham.com/showthread.php?2716-Raspberry-Pi-Mobile-Part-2-Pi-as-a-TNC-Terminal

APRS
 If you can make the RPi behave with your TNC, you should be able to do APRS as well.  The Program for Linux-based APRS is called XASTIR.

IGATE / DIGIPEATER-in-a-box
 APRX

PSK31
FLDIGI

 Let’s Collaborate and have fun !!