Mini-Turtle Logo User’s Guide

Introduction

                      

(graphics not in relative scale)

When you first start the program, the two most important elements to recognize are the “Console

window, and the “Turtle Drawing Area”.  Each are pictured above.  The Console window is where

you type Logo commands, and you will see the effects of those commands in the Turtle Drawing

Area.

Part 1: Built-in Lessons

Once you launch the program, one of the best ways to begin learning how to use it is to activate its

built-in lessons.  Mini-Turtle Logo has 7 step-by-step lessons built right in to get you started. Just

type Lesson 1 into the Console window, (followed by the ‘Enter’ key), to start your first lesson. A

small lesson window will appear and the lesson wil begin speaking to you.  Inside this window is a

button to move to the next step, and a button to have a the current step spoken to you again.  When

the lesson ends, the lesson window will disappear.  You can run any of the 7 lessons at any time.

Just type the word “Lesson” followed by its number into the console window.

Lesson 1:        Using fwd and rot in the console window.

Lesson 2:        Creating your first Logo program.

Lesson 3:        Introducing  PenSz  and  PenRGB.

Lesson 4:        Using parameters in your program.

Lesson 5:        Introducing Repeat-Loops.

Lesson 6:        PenUp,  PenDn,  and using variables.

Lesson 7:        Introducing If-Then Statements.

(Please note.  These lessons use speech capabilities built in to Windows.  In Windows XP, this feature

is far less mature than in Windows 7 & 8.  So XP users must adjust expectations.)

Part 2: The two most basic commands:

fwd  distance

Moves the turtle forward in the direction that it is facing.  In most cases, it will cause the turtle to leave a

straight line trail behind it.

rot  degrees                

Rotates the turtle an additional left turn amount from where it is currently pointing.  Rotational amounts are

measured in degrees.  A full circle turn is 360 degrees.  An about-face turn is 180 degrees.  A quarter turn

is 90 degrees.

Try It!  Type the following lines into the Console:

Rot 20

Fwd 200

Rot 90

Fwd 200

Rot 90

Fwd 200

Rot 90

Fwd 200

And this is what you will get.

Part 3: Printing and Saving Images

               Pressing the Print Button will activate your computer’s default browser. It will immediately

display your current Logo drawing. From your browser program, simply select “Print” in the same way that

you would print any web page.  Also, if you “right-click” on your drawing with the mouse, you can save

the image as a jpeg file in a stored location that you specify.  Simply select the “Save image as” option.

Part 4: Four more commands to control the Turtle’s trail:

penUp

Picks up the “pen”.  Once the pen is up, all forward motions of the turtle will NOT leave a trail.  The turtle will

still move, but it will not leave a trail.

penDn

Puts the pen back down.  Once the pen is down, the turtle will start leaving trails again when it moves

forward.

penSz width

Adjusts the width of the trail left behind by the turtle.  The default value is 1.  A width of 2 will leave a trail with

a width of two pixels.  Higher numbers will cause even greater widths.  Entering a pen size of zero will work

the same as entering a pen size of 1.

penRGB red, green, blue

Changes the color of the trail.  Pretend that you are mixing three colors of paint… red, green, and blue.  Each

color can have a value between zero and one-hundred, (0...100).  This is the first command that is followed by

more than one value.  As the format shows, commas must be present in-between the values.  If you have

equal amounts of each color, then a grayish color will be produced.  All three colors set to zero will produce

black.  All three set to 100 will produce white.  All 50’s will produce a middle gray.  If you want a bright green

color, set your green value at 100, and set your other two color values at 0 (zero).  Try experimenting with

different combinations.  Red + Green = Yellow.  Red + Blue = Magenta.  Green + Blue = Cyan.

Part 5: Four more commands for general housekeeping:

clr

Simply clears any drawing that the Turtle has made.  The entire field becomes a clean slate.

home

Send the Turtle immediately back to its center position, facing due east, just like it started at the beginning.

loc  x-coordinate, y-coordinate

Places the Turtle at any location you desire.  The Turtle’s direction remains unchanged.  The center of the

field is at  location (0,0).  Positive x-coordinates are to the right.  Negative x-coordinates are to the left.

Positive y-coordinates are upward.  Negative y-coordinates are downward.  Here is a grid that shows the

coordinate system:

dir  degrees

Immediately sets the direction that the Turtle faces.  You specify a degree value between 0 and 360.  

0 degrees causes the Turtle to face due east.  90 degrees = due north, 180 degrees = due west, and

270 degrees = due south.

Part 6: Four final commands (for use only in Logo Programs):

getX()   &   getY()

As you write Logo Programs, you may want to store the current location of the Turtle into variables.  You

do this with the getX() and the getY() commands, for example:

set currentXcoord = getX()

set currentYcoord = getY()

Please note: As the example shows, you must use the parenthesis in these commands.

getA()

You can also store the Turtle’s current angle direction into a variable:

set currentAngle = getA()

random( range )

Sometimes it’s fun to add some randomness to your programs.  A random number is stored into a

variable each time you use the random(...) command.  A range must be specified inside the parenthesis.

For example:

set newAngle = random( 360 )

        

Each time this line of code is executed, a random number from 1 to 360 is stored in the variable named

newAngle.

Part 7: Building Logo Programs:

Coming soon.  For now, the best way to learn how to build Logo Programs is to run built-in lessons

2 through 7.  (See Part 1 above)