15. Filling curve as an exemple

And now let's try to draw something like this interesting curve know as "Moore curve".
The underlying algo allows to fill a square in the methodical way.

The main purpose remains to test the ability to move the pen on the paper with the plotter:

And it works pretty well.

Actually I tried it with different different size of the square.

I also tested on a millimeter paper how precise my drawing was: its already nice yet there's room for improvement.

14. Z: moving the pen up & down

An additional stepper motor is required to move the pen up and down. For that purpose, a small 28BYJ48 should be enough:

Imax = 200 mA

To learn how A4988 driver works, here is a good explanation:



As per this explanation and documentation, VRef x 2 = Imax

Therefore VRef should be set to 0.100 V. Done.

Now the mechanics and electronics are ready:

And we can proceed with the first test, with a ball pen: