Scratch 1.4: Beginner's Guide

Table of Contents

Scratch 1.4 Beginner's Guide

Credits

About the Author

About the Reviewer

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code for the book

Errata

Piracy

Questions

1. Welcome to Scratch!

What is Scratch?

21st century learning skills

How to use Scratch?

Programming concepts

Programming limitations

Scratch anatomy

Building blocks

Write the script

Watch the story

Built-in image editor

Interface promotes tinkering

Learning Scratch

Welcome to Scratch!

Installation

Start Scratching

Graphics and Slideshows

Storytelling

Arcade Games

Games of Fortune

Math and Finance

Share!

Real-world stimuli

Summary

2. Installation

Install Scratch

Windows

Run Scratch from flash drive

Integrate Scratch with the PortableApps.com suite

Installation on Macintosh

Run Scratch on USB flash drive

Installation on Linux

Troubleshooting

Limitations

Wine and Scratch

Confirm Java install

Customize your Scratch installation

Redistribute Scratch freely

Source code license

Share alike

Summary

3. Start Scratching

The interface at a glance

Time for action – first step

What just happened?

Basics of a Scratch project

We're all actors on Scratch's stage

Pop quiz

Time for action – save your work

Set the cat in motion

Time for action – a big step

What just happened?

Coordinating a sprite's location

Double-click control

Pop quiz

Time for action – in motion forever

What just happened?

Loops play it again

Time for action – get out of the corner

What just happened?

Have a go hero

Undo an action

Pop quiz

Add sprites to the stage

Get new sprites

Time for action – spin sprite spin

What just happened?

Have a go hero

Pop quiz

Sometimes we need inspiration

Browse Scratch's projects

Time for action – spinner

What just happened?

Costume versus background

Time for action – broadcast a message

What just happened?

Broadcast messages coordinate sprites

Pop quiz

Browse the Scratch community

Time for action – create an account

What just happened?

Abide by the terms of use

Time for action – download a project

What just happened?

Creative Commons

Have a go hero

Summary

4. Graphics and Slideshows

Happy birthday wishes

Time for action – paint a happy birthday sprite

What just happened?

Interface design

Set the stage

Time for action – paint the stage

What just happened?

Adding gradients

Have a go hero

Pop quiz

Sprite costumes

Time for action – address the card

What just happened?

Working with sprites

Animating the card

Time for action – hide all sprites

What just happened?

Time for action – display happy birthday

What just happened?

Sprite names

Time for action – roll call

Choose appropriate names

Graphical transformations

Time for action – give me an M

What just happened?

Loop with repeat

Pop quiz

Incremental improvements

Time for action – give me another M

What just happened?

Time for action – set first M straight

What just happened?

Have a go hero – give me an O

Beware of gaudiness

Time for action – give mom flowers

What just happened?

Ghosting an image

Have a go hero

Parallel execution

Next steps

Build a photo slideshow

Time for action – insert a title screen

What just happened?

Time for action – import photos from disk

What just happened?

Image formats

Working with images

Resize images

How to measure images

Time for action – flip through the photos

What just happened?

Have a go hero

Building audience participation

Time for action – present your show

Pop quiz

Next steps

Summary

5. Storytelling

Barnyard humor

Table of contents

Time for action – create TOC

What just happened?

Have a go hero

Add pages to our book

Time for action – add new pages

What just happened?

Hide that sprite

Time for action – hide the sprites

Introducing the horse

Time for action – import the horse

Costumes versus sprites

The horse speaks

Time for action – the horse talks

What just happened?

Synchronize the action

Time for action – revise the horse talks exercise

What just happened?

Sound

Time for action – a horse whinnies

What just happened?

Sound formats

The dog enters

Time for action – bring out the dog

X and Y coordinates mark the spot

Time for action – stay dog

What just happened?

Position on the grid

Pop quiz

Pointed in the right direction

Time for action – turn to the left

What just happened?

Degrees of direction

Sound effects

Time for action – hit the cymbals

What just happened?

Select an instrument

Time for action – applause, please

What just happened?

Play a note

Have a go hero

Pop quiz

Piece the dog scene together

Time for action – joke, please

What just happened?

Have a go hero

Control the story

Time for action – hide TOC

What just happened?

Have a go hero

Time for action – enter dog

What just happened?

Time for action – exit dog

What just happened?

Have a go hero

Time for action – show TOC

What just happened?

Have a go hero

Build sequence

Have a go hero

Next steps

Summary

6. Arcade Games

Troll pong

Time for action – open the sample pong project

What just happened?

Dynamic interaction

Variables

Time for action – change direction

What just happened?

Time for action – remove the random turn

What just happened?

Have a go hero

Customize the sprites

Time for action – beach ball pong

What just happened?

Have a go hero

Time for action – add new paddle controls

What just happened?

Play theme music, forever

Time for action – add background music

What just happened?

Do something, forever

Working with sound

Have a go hero

Pop quiz

Forever, on one condition

Time for action – paddle meets ball

What just happened?

Start single stepping

What just happened?

Conditional statements

Pop quiz

What's the score?

Time for action – add a score variable

What just happened?

For all sprites

For this sprite only

Time for action – count the paddle's steps

What just happened?

Global versus local variables

Have a go hero

Add a second level

Time for action – reach for a new level

What just happened?

Comparisons

Troubleshooting

Time for action – fix the script

What just happened?

Using Boolean logic

Pop quiz

Add levels

Time for action – count the levels

What just happened?

Have a go hero

Time for action – enter project notes

What just happened?

Next steps

Summary

7. Games of Fortune

Fortune-teller

Time for action – create a list of questions

What just happened?

Have a go hero

Work with an item in a list

Import a list

Time for action – import a list of fortunes

What just happened?

Reasons to import

Export a list

Pop quiz

Your fortune is …

Time for action – tell me a fortune

What just happened?

Time for action – force a positive fortune

What just happened?

Counters

Keep track of intervals with mod

Have a go hero

If/else

Pop quiz

Repeat the fortune

Time for action – my fortune is what?

What just happened?

Holding text in a variable

Do you have a question?

Time for action – ask your question

What just happened?

Add the question to the list

Time for action – add it to the list

What just happened?

Join two text phrases

Time for action – join two sentences

What just happened?

Nest join blocks

Additional string operations

Next steps

Summary

8. Math and Finance

Double it or lump sum?

Double it

Time for action – calculate the double amount

What just happened?

Have a go hero

Time for action – set user-defined variables

What just happened?

Start single stepping

Time for action – slow it down

Graph the values

Time for action – set the graph’s origin

What just happened?

Time for action – draw a graph

What just happened?

Mathematical functions

Create patterns with stamp

Pop quiz

Connect the dots

Time for action – connect the dots

What just happened?

Time for action – fix the graph

Follow a sprite with the go to block

Draw with the pen tool

Time for action – draw the x and y axis of the grid

What just happened?

Have a go hero

Label the newAmount value

Time for action – label newAmount

What just happened?

Pop quiz

Find the interest earned on a lump sum

Time for action – calculate interest on lump sum

What just happened?

Have a go hero

Round to nearest whole number

Have a go hero

Next steps

Summary

9. Share!

Share with the Scratch community

Reduce file size

Time for action – compress media files

What just happened?

Share!

Time for action – share!

What just happened?

Tag it

Update a project

Trouble?

Firefox display problems

Variables change positions

Link to your project

Embed in a blog post

Embed an applet or an image?

Share via social networks

Subscribe to projects via RSS

How to subscribe

Host your Scratch projects

Install files to a web server

Time for action – install files on a web server

What just happened?

Limitations of self-hosting

Pop quiz

Summary

10. Real-world stimuli

Import webcam pictures

Time for action – say cheese

What just happened?

Working with camera images

Export a sprite

PicoBoard—what is it?

Order a PicoBoard

Install the PicoBoard

Connect the PicoBoard

Capture sound input

Time for action – switch backgrounds on sound

What just happened?

Have a go hero

Sound as a numeric value

Time for action – use sound to change the sprite's looks

What just happened?

Have a go hero

Click for the next slide

Time for action – click for the next slide

What just happened?

True or false values

Time for action – wait until button not pressed

What just happened?

Step into the light, please

Time for action

What just happened?

Using light to detect motion

Have a go hero

Control motion with the slider

Time for action – slide sensor

What just happened?

Using gravity

Have a go hero

Create circuits

Time for action – complete the circuit

What just happened?

Wiring our projects

Measure electrical resistance

Time for action – measure resistance

What just happened?

Using resistance

Have a go hero

Watch all sensor values

Have a go hero

Pop quiz

LEGO WeDo support

Summary

A. Scratch Resources

Index

Scratch 1.4 Beginner's Guide

Michael Badger

Scratch 1.4 Beginner's Guide

Copyright © 2009 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, Packt Publishing, nor its dealers or distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: July 2009

Production Reference: 1060709

Published by Packt Publishing Ltd.

32 Lincoln Road

Olton

Birmingham, B27 6PA, UK.

ISBN 978-1-847196-76-7

www.packtpub.com

Cover Image by Vinayak Chittar (<[email protected]>)

Credits

Author

Michael Badger

Reviewer

Tom McKearney

Acquisition Editor

David Barnes

Development Editor

Dhiraj Chandiramani

Technical Editor

Abhinav Prasoon

Indexer

Rekha Nair

Editorial Team Leader

Gagandeep Singh

Project Team Leader

Lata Basantani

Project Coordinator

Joel Goveya

Proofreader

Jade Schuler

Production Coordinator

Shantanu Zagade

Cover Work

Shantanu Zagade

About the Author

Michael Badger is a technical communicator with a history of helping others use their computer software and technology. For fun, Michael reads computer books and blogs about technology. When he finally decides to disconnect, he spends his spare time fishing, growing pigs, raising honeybees, and tending the family.

Michael also wrote Zenoss Core Network and System Monitoring, a step-by-step guide to configuring, using, and adapting the free Open Source network monitoring system.

Share your feedback about this book at http://www.scratchguide.com.

Writers work hours at a time in isolation, but bringing a book from concept to finished product requires the support of many people. My support starts at home with my wife Christie's encouragement and my son Cameron's early bedtime. Cameron, when you're old enough to read, we'll create some games together.

Early in this project, I received thoughtful, timely, and sensible feedback from my editor David Barnes. Thanks for the great advice.

I thank the reviewer, who took time to read and respond critically to my work for which I will be forever grateful. Know that I appreciate every correction, suggestion, and improvement he offered. This book benefits from his attention.

About the Reviewer

Tom McKearney has been doing custom software development for 16 years on projects ranging from Automated Weather Observation, Vehicle Management Systems, Biometric Identification, Battle Simulations, and various financial applications. He is a self-described geek whose hobbies include tinkering with random electronics parts, beer brewing and reading excessively. Tom lives in the suburbs of Baltimore, Maryland, and currently specializes in Microsoft's .NET technologies while working for Applied Information Sciences (www.appliedis.com) in Reston, Virginia, U.S.

He was previously a technical reviewer of Quality Web Systems: Performance, Security, and Usability, Addison-Wesley Professional (September 2, 2001), 0201719363 written by Elfriede Dustin, Jeff Rashka, and Douglas McDiarmid.

Go to http://www.pearsonhighered.com/educator/academic/product/0,3110,0201719363,00.html for more information about this book.

Preface

When we program, we solve problems. In order to solve problems, we think, take action, and reflect upon our efforts. Scratch teaches us to program using a fun, accessible environment that's as easy as dragging and dropping blocks from one part of the screen to another.

In this book, we will program games, stories, and animations using hands-on examples that get us thinking and tinkering. For each project, we start with a series of steps to build something. Then, we pause to put our actions into context so that we can relate our code to the actions on Scratch's stage. Throughout each chapter, you'll encounter challenges that encourage you to experiment and learn.

As you begin working through the examples in the book, you won't be able to stop your imagination, and the ideas will stream as fast as you can think of them. Write them down. You'll quickly realize there are a lot of young minds in your home, classroom, or community group that could benefit from Scratch's friendly face. Teach them, please.

What this book covers

Chapter 1 provides an overview of Scratch, its features, and how it can help you teach 21st century learning skills to your children and students.

Chapter 2 guides us through the installation of Scratch on Windows, OS X, and Linux. This chapter also helps you run the Scratch programming environment from a USB flash drive.

Chapter 3 explores the Scratch interface and allows us to create some simple scripts that demonstrate how easily we can build a project. This is a high-speed tour of Scratch that gets us tinkering and thinking about what's possible.

Chapter 4 teaches us how to create an animated birthday card and a slideshow of our favorite photos.

Chapter 5 allows us to horse around as we develop a barnyard humor book that lets us narrate multiple scenes. There's no need to hold the applause.

Chapter 6 takes a classic pong game and gives it a little personality by adding a troll, switching levels, and keeping score.

Chapter 7 takes us to the fortune-teller, but before we learn the random answers to all our deepest questions, we must create our game using the Magic 8 ball's fortunes.

Chapter 8 uses mathematical formulas and graphs to help us answer the question, Would you rather have a dollar that doubles every day or a lump sum of money? The answer may surprise you.

Chapter 9 explains how to share your project with the Scratch community and how to promote it to you friends and fans.

Chapter 10shows us how to connect a webcam and an external sensor board to our computer and delivers real-world stimuli as input to Scratch projects.

What you need for this book

All you need is an imagination and a willingness to experiment. You will also need a computer with Scratch 1.4 installed. Most modern computers should easily run the latest version of Scratch; however, the Scratch team makes Scratch 1.2.1 available on the Scratch Download page for older systems. Here are the system requirements as defined by the Scratch team:

Display: 1024 x 768

16-bit color or higher

Disk Space: At least 120 MB

Operating Systems:

Windows 2000 or higher for Scratch 1.3

Windows 98 users can use Scratch 1.2.1

Mac OS X 10.4 for Scratch 1.3

Mac OS X 10.3 for Scratch 1.2.1

Linux support via WINE

Native Linux support is experimental

If you want to take advantage of Scratch's audio and recording features, you will need a sound card, speakers, and a microphone.

Who this book is for

Scratch is a teaching language, so it's ideal for people who want to learn how to program or teach others how to program. Educators and parents will learn how to program using Scratch, and they can use Scratch to teach 21st century learning skills to their students and children.

The 21st century learning skills help develop digital literacy by teaching children how to design, think critically, collaborate, communicate, and program in a computer language.

No previous computer programming knowledge is required. If you know how to send email, create documents, or