Question regarding Lego Printer

[Knight3]

I'm currently doing a postdoc, in my home country and I decided its time to build something useful with what I have at the moment (Unfortunately, I have left a lot of legos at my granny's place).

I would like to build a lego printer out of EV3.

(Edit : I can also use the Powered Up system as well)

I pretty much have an idea on how to build a physical (lego) printer - one motor to control the X-axis, and the other motor to control the Y-axis. (We could add in another motor to just control the pen, but that's optional) And if I want to print something, like letter "A" - just program it to make three line strokes, so that it looks like an "A".

Well, that is the gist that I have.

However, I can't wrap around how to make the lego printer to actually print an image file, like a real printer.

Of course, after this, I would love to move on, to make a 3D printer as well.

(I'm good with Python and other programming languages like Java, and am familiar with algorithms. And I heard ev3dev is good? Also I am familiar with html/css/javascript - just know how it works. I'm not good with it though)

 

So here is my question :

How do you make an interface between the lego ev3 and the computer, so that the lego printer can actually print an image file? How does it work? What are the steps involved to make one?

Edited October 10, 2023 by Knight3

[2GodBDGlory]

I'm no expert on that kind of question, but this here looks like a model somewhat similar in concept; perhaps you can learn something from it!

http://sariel.pl/2023/08/mindstorms-pen-plotter/

[pleegwat]

For any research, you definitely want to look at plotters rather than printers.

[Mr Jos]

Here's a model Anton has been working on for a long time, making many iterations.

I've seen it do multiple styles of drawing in person, and it looks really cool.

[dr_spock]

Maybe something with CNC process steps to draw out the image file?

-Have the computer convert the image file to a vector based image.

-Generate GCODE drawing paths from the vector image.

-Send to the GCODE to EV3.

-Have the EV3 parse the GCODE to command the servo motors in moving the pen on a piece of paper.

 

If you can get your EV3 to understand GCODE, then it could open the door to a whole bunch of other stuff like 3D print, laser engrave, drag knife cut vinyl decals...

 

[Sokolov Edward]

Mould King recently released its 13181 pen plotter. It uses 3 conventional L-motors and a Bluetooth remote control unit. Assembly instructions are available in the manufacturer's Facebook thread.

[MAB]

There are instructions for a CNC style plotter for mindstorms (the 51515 kit) available on their app. It is sort of impressive what you can do with LEGO, but actually not a very good plotter at all. There is a lot of kickback, meaning the lines are not particularly accurate. I guess really the question is do you want to build it for fun / for a project, or do you want to build it to use it more seriously. For a project, they are great. For professional output, not.

[Mr Jos]

If you would take a gantry and add a pen, you could make a vertical speed plotter (maybe need to change the 40T gears with 24T, to increase stability instead of having high speeds.

 

[ord]

20 hours ago, Sokolov Edward said:

Mould King recently released its 13181 pen plotter.

Hm, it looks awfully similar to my plotter design:

 

On 10/11/2023 at 3:19 PM, dr_spock said:

Maybe something with CNC process steps to draw out the image file?

-Have the computer convert the image file to a vector based image.

-Generate GCODE drawing paths from the vector image.

-Send to the GCODE to EV3.

-Have the EV3 parse the GCODE to command the servo motors in moving the pen on a piece of paper.

This is basically how I did it @Knight3, except with a Robot Inventor hub rather than EV3. There is a lot of detail in the WIP thread here (including the python program I wrote in pybricks):

I highly recommend the command-line tool "vpype" and a plugin for it called "vpype-gcode". They are purpose built for plotter vector graphics, and with them you can convert any .svg file into gcode, which you then just paste into a program and run it (feel free to use/copy mine).

[Sokolov Edward]

7 hours ago, ord said:

Hm, it looks awfully similar to my plotter design:

This one is simpler than yours in terms of controls, which are the same as those of a regular Lego car. And the design and principle of operation of all flatbed plotters is almost the same.

Edited October 12, 2023 by Sokolov Edward