--- NXT Plotter ---

This plotter is build with the new mindstorms NXT. Except for the pen,
it consists pure of lego parts. It  has 3 motors. One for driving the 
paper through, for moving the cartridge and for lifting the pen. 
The plotter makes use of the rotation sensors inside the motors to move
accurate.

With moving the motors separate, it's only possible to draw perpendicular
lines on the paper; which is not really interesting! By moving with 
little steps in both directions a (bent) curve can be aproximated, which
makes things more interesting!

Instead of programming each little step, I wrote a programm that draws
Bezier-curves (curves with a fixed begin and end point, each having a
controlpoint) by only giving the four points needed for it.
As you may guess, the estimations of the controlpoints to get a desired
curve may be difficult. To solve this problem I used Adobe Illustrator
which is based on Bezier-curves.

After a few curves I got bored by typing in all the controlpoints, so
I thought about a programm which could do this. Therefore I needed to
understand the file structure of Illustrator files.


And here it is! The software I wrote makes it possible to convert an
Illustrator file into an NBC file which is automatically downloaded to
the NXT. So all I have to do is draw an nice image, run my programm
and push the start button on my NXT. It then plots the image fairly
accurate!

More to come....

Comments or questions,
svisser@click2c.net

-- 0937