logothings

Arrow.Keys

Using Arrow Keys to Control a Turtle

If you are in a hurry, just copy the procedures and paste them into your Logo. Then remember to run the move procedure forever.

Make a turtle button, a procedure or just type the following into the command center:

forever [t1, move]

Don’t forget to talk to the turtle you want to control.

On Macs

to move
move1 ascii readchar
end
to move1 :key
if :key = 28 [seth 270 fd 5]
if :key = 29 [seth 90 fd 5]
if :key = 30 [seth 0 fd 5]
if :key = 31 [seth 180 fd 5]
end

On PCs

to move
move1 ascii readchar
end

to move1 :key
if :key = 37 [seth 270 fd 5]
if :key = 39 [seth 90 fd 5]
if :key = 38 [seth 0 fd 5]
if :key = 40 [seth 180 fd 5]
end

If you want to add more keys to move1, you have to find their ASCII code. The Standard ASCII code contains 128 numbers from 0 to

1. These are the same on MACs or PCs. For example on either system ascii "A is 65 and ascii "a is 97.

Another 128 characters make up the Extended ASCII code. This set usually differs on Macs and PCs. The arrow keys belong to this extended set. Finally for Logo to accept non-printing characters readchar is needed. The following instruction will let you find ASCII codes.

show ascii readchar

By the way, char will let you find what the ASCII number represents.

show char 97
a

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