First project-6 DOF drawing robotic arm

Projects General Guidance
1

Hi all, my name is Francesco, I’m from Italy, and as my first project with Arduino, I would build a 6-DOF robotic arm able to draw using pen or copic markers (see below for further development) I saw several project that use motors for a “XY-plotter” but I would have an arm because of usage of multiple copic markers, but I want to detail this step later.

I use graphite pencil or charcoal pencil to draw, I decided to avoid both because I can’t imagine how to check eventually a broken pencil, so my first idea was to use a Bic ballpoint pen to complete my draw.

What I want to do is convert (using octave) my starting image, and I’m coding octave in order to have several lines drawn using pen instead of gray tones. My idea is convert image in gray tones, posterize it and associate to gray areas different dots density in order to have a “dotted image”. Then using bezier curve on a random subset of point, I create a “scribbled image”. Adjusting contrast, brightness and weight for RGB I have almost a realistic imagic.

This is the input for arduino (first question: which board is suitable? I’m in doubt between Arduino UNO Rev.3 and Arduino Mega 2560 Rev.3) that I will convert to vector image and then in g-code. Now I would use g-code in order to control 3 stepper motors, will I need a shield? Which pone is OK this kind of project?

So, I would have a preprocessing in order to have g-code, then put data in arduino that, via a shield, should control 3 angles/rotation direction and speed; is it correct my approach or there is something wrong?

6-DOF is needed because I would develop an upgrade using an end effector able to hold 5 or 6 copic markers (3d printed pen holder) and use one of them for each gray area to be covered.

Can someone address me to the correct arduino board to buy and CNC shield to control stepper motors? But most of all, please tell me if there is wrong things written above! J

Im’ looking for a clean 3d printer robotic arm on thingiverse, I’ll update when I identified correct one.

Thank you!

Grazie

Francesco

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FrancescoPiantedosi:
Hi all, my name is Francesco, I’m from Italy, and as my first project with Arduino, I would build a 6-DOF robotic arm

Don't you think that may be just a little bit too ambitious for a first project?

Even someone with a lot of Arduino experience would approach a project like that as a series of small learning / development steps.

And, in addition to any programming challenges the construction of the mechanical system will not be trivial. To draw accurately you will require a mechanical system with very little backlash and very repeatable motion.

...R

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Hi Robin2, although you have not answered any of my questions, and made no doubts, you have answered an important question: what will be the name of the robot? I'll call him "ambitious"! Good boy! :slight_smile:

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FrancescoPiantedosi:
Hi Robin2, although you have not answered any of my questions, and made no doubts, you have answered an important question: what will be the name of the robot? I'll call him "ambitious"! Good boy! :slight_smile:

That does not reassure me about the likelihood of the project reaching completion.

...R

5

Have you ever seen a robot arm drawing? Not in a movie. I mean in real life.

It simply isn't done. Pen plotters do not use arms in real life. It is a gigantic problem. So gigantic that you could build several different pen plotters for the same amount of effort as making an arm work.

Here is a neat way to do it with an Arduino. You could get this version working in a few hours: YouTube String Plotter (10 minutes)

If you want to change pens then either have a simple wheel of pens on the end effector or a rack of pens off to one side and a pickup mechanism on the end effector. No robot arm required.

6

Can someone address me to the correct arduino board to buy and CNC shield to control stepper motors?

Wrong way around.

Choose the Arduino board after you have built the arm, which includes choosing the correct motors to drive the arm, then choosing the correct motor drivers for those motors.