
C H A P T E R 1 1
A N I N T R O D U C T I O N T O S C R A T C H
163
Ten steps isn’t a very large value, so click on the value
10
and change it to
30
. The block
should then read
move 30 steps
. An animation of a cat moving to the right of the stage
isn’t that interesting, however, so switch to the Sound block palette and drag the
play
sound meow
block to the Scripts area and link it beneath the existing
move
block. To keep
the cat in this position for a while, add in a
wait 1 secs
block from the Control block pal-
ette. Without this, the sprite will appear to flick quickly between its starting position and the
target position.
To make it so the program can be run multiple times without the cat sprite disappearing off
the edge of the stage, add another
move 10 steps
block beneath the
play sound
block
and modify it to read
move -30 steps
. Scratch will happily allow you to use negative fig-
ures like this: if a value of
30
makes the sprite move a certain distance to the right,
-30
will
make it move the exact same distance in the opposite direction.
Finally, add the
when [flag icon] clicked
block from the Control block palette to the
top of the Script area’s stack of blocks to complete the program as shown in Figure 11-5.
Clicking the green flag icon on the top-right of the screen will trigger the program—make
sure you’ve got speakers or headphones connected to the Pi for the full effect!
Figure 11-5:
The completed
animation
program in
Scratch
Summary of Contents for A
Page 1: ......
Page 2: ......
Page 3: ...Raspberry Pi User Guide 2nd Edition...
Page 4: ......
Page 5: ...Raspberry Pi User Guide 2nd Edition Eben Upton and Gareth Halfacree...
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Page 26: ...R A S P B E R R Y P I U S E R G U I D E S E C O N D E D I T I O N 10...
Page 28: ......
Page 29: ...Chapter 1 Meet the Raspberry Pi...
Page 37: ...Chapter 2 Getting Started with the Raspberry Pi...
Page 56: ......
Page 57: ...Chapter 3 Linux System Administration...
Page 79: ...Chapter 4 Troubleshooting...
Page 89: ...Chapter 5 Network Configuration...
Page 109: ...Chapter 6 The Raspberry Pi Software Configuration Tool...
Page 122: ......
Page 123: ...Chapter 7 Advanced Raspberry Pi Configuration...
Page 140: ......
Page 141: ...Chapter 8 The Pi as a Home Theatre PC...
Page 151: ...Chapter 9 The Pi as a Productivity Machine...
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Page 161: ...Chapter 10 The Pi as a Web Server...
Page 172: ......
Page 173: ...Chapter 11 An Introduction to Scratch...
Page 189: ...Chapter 12 An Introduction to Python...
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Page 218: ......
Page 219: ...Chapter 13 Learning to Hack Hardware...
Page 234: ......
Page 235: ...Chapter 14 The GPIO Port...
Page 249: ...Chapter 15 The Raspberry Pi Camera Module...
Page 265: ...Chapter 16 Add on Boards...
Page 280: ......
Page 281: ...Appendix A Python Recipes...
Page 287: ...Appendix B Raspberry Pi Camera Module Quick Reference...
Page 293: ...Appendix C HDMI Display Modes...