2010 04 24 PSCSTA Scribblers

8/9/2019 2010 04 24 PSCSTA Scribblers

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Python and

Scribbler Robots

Hlne Martin

Puget Sound CSTA

April 24th, 2010

Special thanks to Marty Stepp for some formatting and contentFriday, April 23, 2010


2/23

Hlne Martin

Bachelors in CS from UW

Career and Technical Ed through South Seattle

Teach at comprehensive public high school

Five periods of computer science

- 2x Exploring Computer Science- 2x Creative Computing- 1x AP Computer Science

http://garfieldcs.com

Friday, April 23, 2010
http://garfieldcs.com/http://garfieldcs.com/http://garfieldcs.com/


3/23

Game Plan

Why bother with Python

Python language basics

Why bother with Scribblers

myro package basics

Play!



4/23

Why Teach Python?

Light-weight syntax

Scalable (small hacks to GUI apps)

Lots of great libraries- myro (today)- pygame- scipy

InterpretedPermissive

Used increasingly in college courses



5/23

Why Not Teach Python?

Permissive

Dynamically typed (values have types, but not

variables)

Too many ways to skin a single cat!

Not used much in corporate world

- Though YouTube, Google, Yahoo!, NASA make some use of it



6/23

Getting Python

Free at http://python.org

Generally pre-installed on OS X or Linux

Includes Idle, an IDE

http://python.org/http://python.org/


7/23

Interacting With Python

Programs saved with .py extensions

Commands interpreted straight in shell

Students can get confused about the two!!



8/23

Print Function

Simple! (no System.out.yuck)

Can be called with parameters of different types

Concatenation shows ugliness of dynamic types

Print can dis la different t es

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print("Hello, world!")

print()

print(25)

print("You have " + str(dollars) + " dollars")



9/23

Python Operations

Arithmetic:

- ** (exponent)- * (multiplication) / (division) % (modulus)- + (addition) - (subtraction)

Boolean

- == != < >=- not

- and or

Common Types

- int, float, bool, str



10/23

White Space

Indentation indicates blocks

Super offensive at first glance, but one gets over it

- its NOT like shell scripting!

Colon indicates containers, everything indented

under is governed by that container

In entation matters

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for i in range(3):print("Hello") # repeatedprint(25) # repeated

print("Hi") # not repeated



11/23

Iteration

Definite loop

Indefinite loop

Ba ic for loop structure

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for i in range():


While loop strcture

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while():




12/23

Conditionals

Co ditional structure

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if(): elif():

else:



13/23

Functions

Definition

Calling

- A common error is to forget parentheses after the call

The def ke word is used for definin functions

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def hello(, ):

print("Hello, world!)

hello()hello()



14/23

External Libraries

Import modules to get access to more functions

Usi random numbers

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from random import *

die1 = randint(1, 6)die2 = randint(1, 6)



15/23

Python Resources

http://python.org/

http://diveintopython.org

http://openbookproject.net//thinkCSpy/

http://openbookproject.net//thinkCSpy/http://openbookproject.net//thinkCSpy/http://diveintopython.org/http://diveintopython.org/http://python.org/http://python.org/


16/23

Scribblers



17/23

Why Teach With Scribblers

Visual and tactile feedback is motivating

Opportunity to discuss robotics

Cool factor

Indestructible and no assembly necessary

Uses a real language



18/23

Why Not Teach With Scribblers

Flakiness leads to frustration

Too many things going on

Limited interesting applications



19/23

My Successes

Python as primary language in Creative

Computing

- 120 students so far

2 week unit on Scribblers for Creative

- Students already know a lot of Python

Great projects: object detection, piano,

obstacle course completion



20/23

My Challenges

Python as quick introduction to real language

after Scratch in Exploring Computer Science

1 week intro to Scribblers for ExploringEnded unit early because students just werent

getting it and flakiness was irritating!



21/23

myro

Python library gives access to Scribbler functions

Co e needed to et oin with m ro

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from myro import *init()



22/23

A Sample Program

def flashLight(times):for i in range(times):

setLED("back",1)wait(0.55)setLED("back",0)wait(0.25)

def senseLoop():# getLight() is a function that gives back three values# Here we save them in three variables.rightSensor, centerSensor, leftSensor = getLight()

# Print out all three sensor valuesprint "Light Sensor Values:", rightSensor, centerSensor, leftSensor;

# If the right sensor is coveredif rightSensor > 2000:

# You can write a song using note names and beat lengthsplaySong(makeSong("c 1; g 1/4; a 1/2; e 3/4;") )# Make the back LED flashflashLight(5)

if centerSensor > 5000:print "BAGELS BAGELS GGRRAA" # don't ask; it's latewait(0.25)beep(0.25,440,880)

if leftSensor > 2000:turnLeft(1,0.5)

# Continue sensing for 20 secondswhile(timeRemaining(20)):

senseLoop()



23/23

Play Time!

Documents

2010 04 24 PSCSTA Scribblers