Teach your kids how to program with Python and the Raspberry Pi

RaspberryPis are the new frontier in enabling kids (and curious adults) to get access to an affordable and easy-to-program platform to build cool things. Over a million of these nifty little devices have been sold in less than a year and part of their popularity has been due to how easy it is to start programming on them.

In this session you'll learn how to get started with the Raspberry PI, initial set-up, configuration and some tips and tricks. Then we'll have a brief introduction to basic Python and we'll write a few simple programs that run on the RaspberryPI. The last section of the session will be dedicated to PyGame, we'll learn about surfaces, events, inputs, sprites, etc and demonstrate how to build very simple games that are as much fun for kids to write, than to play!

Transcript

1. PLATINUM)SPONSORS)
   GOLD)SPONSORS)
   SILVER)SPONSORS)
   Saturday, May 4, 13
   

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2. Juan Gomez
   Co-Founder of PyhtonKC
   Twitter: @_juandg
   Teach your kids how to
   program with Python
   and the Raspberry Pi
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3. May the 4th be with you!
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4. So what is this talk really about?
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5. Brief History of the RaspberryPi
   More at: https://www.youtube.com/watch?v=z-j4USHTLWM
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6. Saturday, May 4, 13
   

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7. What you’ll
   need:
   • MicroUSB Power Supply
   • SD Card (>= 4GB)
   • USB Keyboard
   • USB Mouse
   • Ethernet Cable
   • HDMI Cable
   • Monitor
   • Case?
   • HDMI to VGA Adapter?
   • USB WiFi Adapter?
   • USB to TTL Cable?
   • RCA Cable?
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8. How do you teach
   kids?
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9. Make it fun!
   http://www.adafruit.com/products/975
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10. Some tips
    • Seriously, Make it fun!
    • Start with Math
    • Be Patient
    • Explain the Basics
    • Use real life examples
    • Kids are slow typists!
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11. How do I set it up?
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12. Saturday, May 4, 13
    

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13. Disclaimer
    • This an intro to Python for YOU, not your
    kids.
    • The kids version is at: https://github.com/
    mechanicalgirl/young-coders-tutorial
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14. A Python Code Sample
    x = 34 - 23 # A comment.
    y = “Hello” # Another one.
    z = 3.45
    if z == 3.45 or y == “Hello”:
    x = x + 1
    y = y + “ World” # String concat.
    print x
    print y
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15. Enough to Understand the Code
    • First assignment to a variable creates it
    • Assignment is = and comparison is ==
    • For numbers + - * / % are as expected
    • Special use:
    • + for string concatenation
    • % for string formatting (as in C’s printf)
    • Logical operators are words (and, or, not)
    not symbols (&&, ||, !).
    • The basic printing command is print
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16. Comments
    •Start comments with #, rest of line is ignored
    •Can include a “documentation string” as the first
    line of a new function or class you define
    •Development environments, debugger, and other
    tools use it: it’s good style to include one
    def my_function(x, y):
    “““This is the docstring. This
    function does blah blah blah.”””
    # The code would go here...
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17. Python and Types
    •Everything is an object!
    •“Dynamic Typing”-> Data types determined automatically.
    •“Strong Typing” -> Enforces them after it figures them out.
    x = “the answer is ” # Decides x is string.
    y = 23 # Decides y is integer.
    print x + y # Python will complain about this.
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18. Basic Datatypes
    • Integers (default for numbers)
    •z = 5 / 2 # Answer 2, integer division
    • Floats
    •x = 3.456
    • Strings
    • Can use “” or ‘’ to specify with “abc” == ‘abc’
    • Unmatched can occur within the string: “matt’s”
    • Use triple double-quotes for multi-line strings or strings that
    contain both ‘ and “ inside of them:
    “““a‘b“c”””
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19. Whitespace
    Whitespace is meaningful in Python: especially
    indentation and placement of newlines
    •Use a newline to end a line of code
    Use \ when must go to next line prematurely
    •No braces {} to mark blocks of code, use
    consistent indentation instead
    • First line with less indentation is outside of the block
    • First line with more indentation starts a nested block
    •Colons start of a new block in many constructs,
    e.g. function definitions, then clauses
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20. Assignment
    •You can assign to multiple names at the
    same time
    >>> x, y = 2, 3
    >>> x
    2
    >>> y
    3
    This makes it easy to swap values
    >>> x, y = y, x
    •Assignments can be chained
    >>> a = b = x = 2
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21. A Python Code Sample
    x = 34 - 23 # A comment.
    y = “Hello” # Another one.
    z = 3.45
    if z == 3.45 or y == “Hello”:
    x = x + 1
    y = y + “ World” # String concat.
    print x
    print y
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22. Side by Side with Java
    Java (C#) Python
    public class Employee
    {
    private String myEmployeeName;
    private int myTaxDeductions = 1;
    private String myMaritalStatus = "single";
    public Employee(String EmployeName)
    {
    this(EmployeName, 1);
    }
    public Employee(String EmployeName, int taxDeductions)
    {
    this(EmployeName, taxDeductions, "single");
    }
    public Employee(String EmployeName,
    int taxDeductions,
    String maritalStatus)
    {
    this.myEmployeeName = EmployeName;
    this.myTaxDeductions = taxDeductions;
    this.myMaritalStatus = maritalStatus;
    }
    }
    class Employee():
    def __init__(self,
    employeeName
    , taxDeductions=1
    , maritalStatus="single"
    ):
    self.employeeName = employeeName
    self.taxDeductions = taxDeductions
    self.maritalStatus = maritalStatus
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23. Life is Short
    (You Need Python)
    - Bruce Eckel (Thinking in C++)
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24. Useful books:
    Python for Kids
    http://oreil.ly/10boyUq
    The Quick Python Book, 2nd Ed
    http://amzn.to/lXKzH5
    Google's Python Class
    https://developers.google.com/edu/python/
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25. Let’s start by writing
    text based games
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27. A Skeleton
    • Let’s start with the most basic pygame program
    template.py
    template.py
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    from pygame import *
    from pygame.sprite import *
    from random import *
    init()
    screen = display.set_mode((640, 480))
    display.set_caption('Window name!')
    while True:
    e = event.poll()
    if e.type == QUIT:
    quit()
    break
    screen.fill(Color("white"))
    display.update()
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28. Surface
    • Most of the game elements you see are represented as
    Surface
    • display.set_mode((x, y)) creates your canvas – it
    returns a Surface object
    Useful surface methods:
    • fill("color") fills the surface object it's been called from
    • blit(surface, area) paints the source surface onto the
    rectangle bounded by the area tuple
    –Example: screen.blit(ball, (50,50))
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29. Rect
    • Objects that store rectangular coordinates
    • Call .get_rect()on a surface to get its bounding box
    Rectangle methods/variables:
    • .center holds the object's center as a tuple
    • .colliderect(target) returns True if the parameter
    overlaps with the object
    • .collidepoint(target) returns True if the target point
    overlaps with the object
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30. Media
    • Loading an image:
    –img = image.load("file.gif").convert()
    • Getting a bounding rectangle:
    –img_rect = img.get_rect()
    • Loading and playing a sound file:
    –mixer.Sound("file.wav").play()
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31. Sprite
    • Simple base class visible game objects inherit from.
    Ball.py
    Ball.py
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    from pygame import *
    from pygame.sprite import *
    class Ball(Sprite):
    def __init__(self):
    Sprite.__init__(self)
    self.image = image.load("ball.png").convert()
    self.rect = self.image.get_rect()
    def update(self):
    self.rect.center = mouse.get_pos()
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32. Using Sprites
    • They're just objects: initialize them
    –ball = Ball()
    • Create a group of sprites in main
    –sprites = RenderPlain(sprite1, sprite2)
    • Groups know how to draw and update
    –sprites.update()
    –sprites.draw(surface)
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33. Events
    • User input such as clicking, moving mouse or key presses
    • Add more branches to test the result of event.poll()
    • Events to test for:
    –QUIT
    –MOUSEBUTTONDOWN
    –JOYBUTTONDOWN
    • Testing for the letter ‘d’ being pressed using KEYDOWN
    if e.type == KEYDOWN:
    if e.key == K_d:
    …
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34. Adding Text
    • f = font.Font(font, size) goes before your game loop
    – Example: f = font.Font(None, 25)
    – Usually, None is a good enough font!
    • text = Font.render(text, antialias, color)
    – Example: text = f.render("Hello!", True,
    Color("green"))
    – Returns a surface
    • Must be blit, just like any other surface
    – Example: screen.blit(t, (320, 0))
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35. Let’s dissect a game!
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36. Join PythonKC -> http://
    www.meetup.com/pythonkc/
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37. Juan Gomez
    Co-Founder of PyhtonKC
    Twitter: @_juandg
    Thanks!
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38. PLATINUM)SPONSORS)
    GOLD)SPONSORS)
    SILVER)SPONSORS)
    Saturday, May 4, 13
    

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