Getting Started with Raspberry Pi v1.2

Getting Started with
Raspberry Pi
Otronicon: 18 January 2013

Developed by

Wednesday, January 30, 13

Getting Started with Raspberry Pi

Welcome!
Let’ get started!

This will be fun and you will learn a lot today.

Please follow instructions and only use the Raspberry Pi
when instructed to do so.

Your Raspbery Pi should be running the latest Raspbian OS
available here:
http://www.raspberrypi.org/downloads

Okay... Let’s go!



Let’s Play!
For the first ten minutes today we will play. Go ahead and
right click on the Python Games icon on the desktop and
select open. Click OK on the audio dialog box.
When we are working on the desktop today we will be
opening files by right clicking. Opening files and programs can
be a little slow to start from the desktop environment.

Also, if you double click multiple times, you will open several
versions of the same program, so we’ll use the right click
method to open things as opposed to the wrong click
method today!

Select a game and play!



Shut down!
Shut down Python games by clicking on the close button (x)
in the upper right corner of the Python Game Launcher
window.

From the lower left corner of the desktop, left click and
select logout from the pop up menu.

Click on the shutdown button in the LXDE window.

Don’t worry, we’ll be turning the Raspberry Pi back on in a
few minutes after we discuss how to use it and look at some
amazing examples!



Why buy a Pi?
The ofﬁcial Raspberry Pi Foundation
description:

“The Raspberry Pi is a credit-card sized computer that plugs
into your TV and a keyboard. It’s a capable little PC which
can be used for many of the things that your desktop PC
does, like spreadsheets, word-processing and games. It also
plays high-deﬁnition video. We want to see it being used by
kids all over the world to learn programming.”



Eben Upton
The Raspberry Pi was built so that learning about
computers and programming could be fun! Eben Upton,
the inventor of the Raspberry Pi, used to have fun playing
on and tinkering with computers when he was younger.
Once he started teaching computing at the University of
Cambridge, he noticed that students were no longer
having fun coding with computers. They were just playing
games rather than making them. To improve the situation,
he got together with some friends, started the Raspberry
Pi Foundation, and got to work creating a wonderful little
computer that would be fun to program and play with!



Eben Upton
CNN Moneywatch featured Eben Upton and the Raspberry Pi:

$35 computer can get kids coding

Eben Upton, the man behind Raspberry Pi, hopes to bring
computer programming skills to a new generation.

http://money.cnn.com/video/technology/innovation/2012/12/10/
t-raspberry-pi-kids-coding.cnnmoney/



How is it used?
The Raspberry Pi is used in a lot of ways!
It runs on a Linux Operating System so…
how it works depends on the linux build.

Some builds are very easy to use like Raspian “Wheezy” the
one you are using here today, while others are customized
for speciﬁc tasks. Some other examples are Raspbmc (a
media center distribution), Risc OS, or Plan 9 from Bell Labs.
This operational diversity is one of the beneﬁts of the
Raspberry Pi. But to get started and to remain consistent, we
suggest using Raspbian Wheezy.

http://www.raspberrypi.org/downloads



Look, up in the Sky!
1) Project Black Sky:
https://vimeo.com/user14504880

Project Black Sky is a science project done by a 13 year old
that took a Raspberry Pi up to 85,000 feet in a weather
ballon!

“The Raspberry Pi performed ﬂawlessly during the mission.
While other more expensive electronic devices in the capsule
failed (the Canon camera and the Spot GPS), the Raspberry Pi
never stopped functioning, even through extreme low
temperature and pressure, and a violent descent.”
http://www.projectblacksky.com/



...in a SNES
2) Ted’s Super Nintendo Emulated System:

This project uses the Raspberry Pi to replace the main logic
and graphical components in a SNES. This is one of the more
sophisticated projects done on a Raspberry Pi.

http://www.raspberrypi.org/archives/2984
http://tinyurl.com/SNES-FamiLAB
http://tinyurl.com/snes-hackaday



... as a Media Center
3) An XBMC is an open source, cross platform media center
originally designed to run on the Xbox. Many people are
buying Raspberry Pi’s to use as dedicated media centers.
There are many media center builds. We’ll demonstrate one
here:

Play clip from “Push Pause Play” on openELEC RP.

http://wiki.xbmc.org/index.php?title=Raspberry_Pi

Push Pause Play may be downloaded here:
https://vimeo.com/34608191



...as a Camera Controller
4) Lance R.Vick’s Raspberry Pi Camera Controller:

Lance made his camera rig at FamiLAB. Some of the
FamiLAB members helped him cut the bracket out of MDF
board on a CNC mill to make the camera mount. Other
FamiLAB members helped him build the gears for the rig on
their 3D printers! Lance uses an open source C library
called gphoto. He also uses Python code to bind the C code
into very useful software modules.

https://vimeo.com/50499145
http://lrvick.net/
http://gphoto.sourceforge.net/proj/



...as a Server
5) Raspberry Pi as a web server:

“How to” by Jeremy Morgan
http://tinyurl.com/piwebserver

Solar Powered FTP!:
http://tinyurl.com/solarftpserver



...Minecraft?
6) Minecraft Pi Edition:

Mojang and the Raspberry Pi foundation announced Minecraft
Pi Edition in November. It is due to be released soon!

http://www.raspberrypi.org/archives/2872

Keep an eye on the main Raspberry Pi foundation blog and
forums to see what else is happening on the RP!

http://www.raspberrypi.org/


Raspberry Pi Model B

The B model is the ﬁrst RP to come off
of the production line. It has gone
through at least 3 major revisions in the
last year. Every revision has brought
major improvement yet not affected the
$35 price point.


Raspberry Pi Model A

The A model is scheduled to start
shipping soon. Lacking an ethernet
connector and having only one usb port
allows the A model to ship at a price of
$25. This simpliﬁed version will also
require less power which will be
attractive for some projects.

Imagine having a “B” model to use a
developers machine, and using “A”
models to deploy in projects.

Many projects will not require wired
networks and a usb hub can provide
many alternatives.



Handling the RP
The Raspberry Pi was built to be used, but not abused. Every
Printed Circuit Board (PCB) should be handled with care.
Handle the RP only by the edges of the board itself.
Avoid touching or holding any of the components on the
board.

Rough handling can cause solder points to fail and may result
in short circuits.

Experiment, but be careful with the GPIO pins as well. A great
reference is the Raspberry Pi Users Guide:

http://www.raspberrypi.org/archives/tag/gareth-halfacree



Order of operations:
Connections to the Raspberry Pi include power, video,
audio, network, usb and general purpose input and output
(GPIO). It is important to make your connections at start
up and shut down in a certain order.



Order of operations:
Power:
As a general rule regarding connectors, power to a system
should be the last thing to be connected and the ﬁrst thing
to be disconnected after a shutdown.

If power is supplied before other connections are made,
bad things can sometimes happen.



Order of Operations:
Make connections in this order:

1) Operating System (SD card)
2) Audio Visual
Display and audio
3) USB peripherals
Mouse, keyboard, hub, etc.
4) Network
5) GPIO (optional)
6) Power

See the ofﬁcial Quick start guide here:
http://www.raspberrypi.org/quick-start-guide



Power up!
Please plug the power cable back into your Raspberry Pi.

As your RP boots up, you will see a report streaming down
the monitor. Eventually the boot sequence will ﬁnish and you
will ﬁnd yourself at the prompt! Don’t worry, this is a good
place to be. A very good place!



Let’s do an update.
Enter the following text into the terminal:

sudo apt-get update
Apt stands for Advanced Packaging Tool. It is used in
the terminal to manage, download and install
packaged ﬁles.

The Apt command you have just entered has updated
and synchronized all of your Raspbian packages.



Let’s ﬁnd Joe.
Let’s search for and install a useful program:
Enter the following text into the terminal:

apt-cache search joe
When you hit your enter key, you will see a list of resources
pouring down your terminal. These are all of the resources
that include the string “joe” in the current Raspbian build on
the Raspberry Pi.
Apt-cache search explores a repository of known software
for the current Raspbian build of the RPs operating system. It
requires a live network connection to locate the remote
ﬁles.



Let’s install Joe
If we see Joe, let’s get Joe. Joe is a programmer’s text
editor that has syntax highlighting for Python and C.
We’ll use Joe to make our ﬁrst program on the
Raspberry Pi!

Enter the text:

sudo apt-get install joe



Let’s work with Joe
Once Joe is done installing, the prompt will show up in the
terminal. When it does, let’s type in the following line:

joe helloworld.py
The command above “calls” up the program Joe, and opens a
new document. It also names the file helloworld.py. If the file
had already existed, then Joe would have simply opened it.
But since we just installed Joe, this single line of code just
created and named a new file.

That’s pretty cool!



Let’s make code
This new ﬁle needs some content. Let’s type in the following
in Joe’s editor section:

print “hello world”
Next, type Ctrl+K to save the ﬁle and “X” to exit Joe.



Let’s run code
After we have used Joe to write our Python code, we’ll
simply use the built in interpreter to run the program.
Type the following into the terminal:

python helloworld.py
The program will run and return the string of text “Hello
world” to the terminal.
You have now written and run your ﬁrst program on the
Raspberry Pi.

Nice work!



Utility time
Before we move to the desktop environment and get
deeper into coding, let’s learn a few more things about
the terminal.
Let’s look for devices! Enter the following:

lsusb
Lsusb lists (usb devices detected) This command
shows all USB devices detected and gives pertinent
data for each. With this information, you can search
through “repositories” that contain software and
ﬁrmware updates related to the devices.



More utility time
Let’s have a look at which modules are running. Enter
the following:

lsmod
Lsmod (lists modules) displays modules open in the linux
kernel.
What’s a linux Kernel? The kernel is the central program
that manages the OS.
A Shell is another program that is used to allow the user to
communicate with the OS. The terminal that you are using
now is a shell.



One More Thing!
Before we go ahead and leave the terminal, we shall gather one more set of
resources and unpack them. Please enter:
wget http://www.raspberrypi.org/game.tar.gz
Wait for the ﬁles to load.

tar xvfz game.tar.gz
This uncompresses the gzipped archive.
Next, enter:
cd game
and ﬁnally:
python snake.py


Snake!
DId you see that? It’s a snake! Made out of the letter “o.”

Use your arrow keys to pick up as many digits as you can.

Play Snake for a few minutes and take a short break!

when you are done playing Snake, enter:

Ctrl+Z



Terminal
At this point we have reached the end of our terminal
session. We hope your ﬁngers are not too tired, as we will be
hacking and mousing around the LXDE next.

So, for your last terminal command please type:

startx
into the terminal and then quickly remove your hands from
the keyboard!



Desktop Session
When the desktop environment loads, please do not open
any programs!

The Raspberry Pi can be very slow in the desktop
environment. Many linux applications run slow in this
environment, so in order for you to be able to operate
follow instructions!

Don’t click on any icons yet!



Shortcuts!
Overview:

Scratch - Block based programming for kids.
IDLE and IDLE 3 - That’s right - 2 versions of Python!
Midori - Default web browser.
PiStore - The new place to get RP stuff.
Debian Reference - The manual that hackers read.
Wifi Config - A gui wifi set up program
LX Terminal - A windowed version of the terminal.
Python Games - A python game arcade.



Scratch Demo!
Let’s right click on the Scratch icon on the desktop!
The cat is named “Scratchy!” She’s a pretty cool cat.

Wait for it! The LXDE may take a few seconds to load
things on the RP processor.

When Scratch opens, click on the control button in
the upper left window (the block palette) to call up
the control blocks.

Announcement: There are FamiLAB
Scratch workshops every morning at 10:30
during Otronicon right here in this room!



Control Blocks
Drag the “When space key pressed” object to
the scripts window.

The Scripts window is the center window.

Place the block near the top.



Audio Blocks
Click on the sound button in the block palette to call
up the sound blocks.

Drag the “play sound meow” block onto
the stage below the command block. Drag the sound
block until it attaches like a puzzle piece to the
command block.



Motion Blocks
Click on the Motion button.

Drag either of the “Turn 15 degrees” blocks so
that it connects to the bottom of the sound block.



Spin Scratchy!
Click on the space bar!



Stop Scratchy!
Scratch is used to teach young students basic
programming structures.

It was developed at the Lifelong Kindergarten Group
at the MIT Media Lab.

Quit Scratch, and don’t save!
Q. Why quit Scratch? A. We have to get that cat out
of here before the giant snake comes back!



LXTerminal
We are going to run some more code in python. We
have already completed the “Hello World” program
back in the terminal using Joe.

Now we are going to run python from the LXTerminal

Go ahead and open the LXTerminal by right clicking
on the desktop icon and selecting open.



List
At the prompt, type in:

ls
(That’s a lower case L and S!)
and hit return.

“ls” lists the ﬁles and directories located within the
current directory level that you are accessing in the
terminal.

We jsut used “ls” to get oriented in the terminal.



Navigate
At the prompt enter

cd game
and hit return.

The CD command tells the terminal to change
directories and open the game directory.

Entering “ls” again will show us the contents of the
game directory.



Interpreter
In the game directory you should find snake.py along
with a few other python files.

Enter

python snake.py
and hit return.

You have invoked the python interpreter by typing
python. Typing snake.py lets the interpreter know which
file to load.



Snake!
Use the arrow keys on your keyboard to guide the
snake!

The space bar will restart the game.

Play a few rounds and then exit Snake.

Enter Control + z to exit snake.



Hack it!
Let’s use Joe to open the .py file and look inside!


joe snake.py
Hit return.You should see the snake.py file
Use your arrow keys to navigate down until you find
the following text:

def snake(scr);
This is the code that defines the snake.



Yellow Snake!
A few lines below the def snake(scr);

change the line that reads:

curses.init_pair(1, curses.COLOR_RED,...

to

curses.init_pair(1, curses.COLOR_YELLOW,...

You may have to enter Shift + S to unlock the text ﬁle
in Joe. If so you will be prompted when you enter the
text.



Longer tail!
Continue to scroll down the code with the arrow key.

Find the text for the tail:

# empty tail

tail = []
length = 10
Go ahead and change the length from 10 to a number
less than 30.



Save it and Exit!

Ctrl + K and then D
This will save the changes to the ﬁle.

Enter

Ctrl + K and then Z


Save and Run it!
Re-run the script by entering:

python snake.py
Did it work?



Thank You!
We’ve been through a lot together. Scratchy asked me
to thank you for saving her from the large snake!

We’ll spend the rest of this session looking at the
examples and exploring the Raspberry Pi. Feel free to
play with python or explore the examples with us!

Don’t forget to come visit us at FamiLAB.


Workshops!
Otronicon FamiLAB workshop schedule:
10:30 a.m. - Scratch: Game Programming for Kids

12:30 a.m. - Introduction to Soldering - Build a Game

3:00 p.m. - Getting Started with Raspberry Pi

5:00 p.m. - Introduction to Arduino

For information about workshops and more:
http://familab.org/


Thank You!
Learn more about FamiLAB here:

http://familab.org/


Getting Started with Raspberry Pi v1.2

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