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Topic: Drawing Bot (Read 3219 times)previous topic - next topic

florisv

Jul 31, 2010, 03:27 pm
hi,

inspired by the Drawbot (http://web.me.com/sami6877/unanything/Site/Secret_Work/Entries/2010/6/1_Drawbot.html) I would like to build and experiment with one similar to that myself. But I wonder How to get started, for example using two kind of motor shields or something else. Usign x- and y-axis bars to move it around, or stick to the orignal.

How to translate an image into a drawing. I think the engine/drawing part is the easiest. but how to translate the image to the drawing instructions is a bit of an enigma to me. i supose using some kind of algorithm in processing might give such a result.

This is a different kind of robot.
http://www.hektor.ch/

tailortrik

#1
Aug 17, 2010, 06:49 pm
Quote
hi,

inspired by the Drawbot (http://web.me.com/sami6877/unanything/Site/Secret_Work/Entries/2010/6/1_Drawbot....) I would like to build and experiment with one similar to that myself. But I wonder How to get started, for example using two kind of motor shields or something else. Usign x- and y-axis bars to move it around, or stick to the orignal.

How to translate an image into a drawing. I think the engine/drawing part is the easiest. but how to translate the image to the drawing instructions is a bit of an enigma to me. i supose using some kind of algorithm in processing might give such a result.

This is a different kind of robot.
http://www.hektor.ch/

Hello, I built that machine and I can tell you what you need to do it.

I spend a few years doing it because the Hektor people would not tell me how.

My system is a little more complicated then a standard X,Y plotter because the two motors do not control x, and y.

basically, the machine is constantly discovering the hypotenuse of two invisible triangles.

Think of the Patagonian theorem. for each point, the arduino will calculate two triangles, (the belts being the hypotenuse)
and move each stepper until it has reached that length.

so, if your first point is 4,5

and the distance between the two motors is 10

then you have to split this into two triangles
the left triangle now has two sides.

4, 5,
and A1 being the length we need to find.

to find the X length of the other side of the triangle, we need to find the remaining distance.
so take your x value and minus 10.
giving you
6,5,B1

you should draw this and end up with one large triangle,
the top bar is 10 long, devided at the 4 point
the two triangles have the same y length being 5, so these sides touch.
now do Pythagorean theorem with the two triangles to find the hypotenuse.

If you have done this correctly, you will find that the let belt must be 6.4 and the right belt is 7.8
Do this in a loop for every point.

use the bresenham algorithm for straight lines.

I can give some code if you would like it.

you don't need two motor shields, just one. Use the Adafruit Motor shield with two 1.8° stepper motors.(pull from OLD printers)
Power externally, watch out for heat.

also see:
http://www.as220.org/labs/drawbot/
http://www.tristanperich.com/Art/Machine_Drawings/

as for as the drawing algorithm. you are going to have to figure that one out yourself.
It is processing though.

hope that helps. Send me an email if you want. its on my website(first link posted)

roypardi

#2
Jan 19, 2011, 05:57 pm
Can you post your bresenham implementation? I've been getting odd/inaccurate results and haven't been able to figure out why.

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