Xy plotter build issues

#1

I have completed the xy plotter build and found issues with the instructions.
there are a number of things taken for granted and unlike your other build instructions there are a number of the build steps which are not clear.
The instructions should be written with very clear steps and pictures there are too many assumption to be made about a few of the steps.
the phone jacks should be labeled for the port to be plugged into, I found the description and pictures left a lot to be experimented with to get it right.
which power jack should be used, there are two one on the arduino board and one on the shield?
Another issue is that the four wires on the stepper motors are not long enough to allow the traveling stepper motor to reach the end of its travel to activate the limit switch.
I also have not gotten a successful drawing out of it yet.
there is xy action and it looks like it may be making the proper movements but the pen control is either working backwards or the actual plot movement is in error.
Rather than there being a smooth draw of a line, it seems to be broken down to a series of points.
The pen is going up and down like it is a dot matrix and not a line draw.
It was fun to build, in spite of the instruction but a disappointment to use so far.

Chris

#2

Hi avtech,

So sorry about this problems of the XY Plotter. We are trying to make a more detailed user guide of this. And make an update soon.

For the problem of the wire, we will send you an extend wire to you. And also we will send you a pen that can draw very well.

So sorry about these issues, we are trying to solve this.

Eric

#3

Eric, no need to send wires and a pen.
I can look after that, thank you for your response though.
I’m glad to hear that you are addressing the issues, I know it is a new kit and it takes time to get things right, it was just a little frustrating.
One thing I am unsure of though, does the plotter need to define the start point or 0,0 to plot properly?
That may be part of my problem, with the one axis not reaching true 0,0 then the whole draw may be thrown off.
Also, should the pen be dropping down and staying down while it draws only lifting when it is finished that part of the plot?
The on screen display of the plot doesn’t seem to be creating the plotted lines as a series of points.
I can send a video if it would help understanding what is happening.

Chris

#4

So the saga continues, I removed the stepper motor controller from the mount so the wires are long enough to hit the Y axis limit switch (looking at the plotter with the controller at bottom left) so all is good there.
the plot looks some what like the drawing now.
The new issue is that the pen holder now hits the carriage on the right during a plot throwing the whole thing off.
There needs to be a limit switch on that side too.
It would be good to have some way of calibrating the x-y extremes so the plotter knows the boundaries.
I agree with the comments from Bram Fetter of The Netherlands about the pen positioning and the addition of another stepper motor for the pen arm.
There is a solution for that which would not require another stepper motor though, adding guide pullys at the four corners with the belt attached to both ends of the x axis and travelling arounf the whole structure would keep both sides in sync.
However, I still have problems with the pen operation and it going up and down at the wrong times creating broken lines when it should just go down make contact with the paper surface and plot the line and lift up so that it can move to its next startpoint without drawing.
I would like to see the software used for the demo videos made available, so far my build has not produced anything like the video shows.
Perhaps I am missing something in either the Sketch compiling (complied and loaded from an iMac) or there needs to be some configuration of the BlueTooth on my Android tablet.
Another question, could the issue be with the Arduino board and would I be able to use another board to control the plotter?

Chris

#5

Just realized that I was wrong when i said" There is a solution for that which would not require another stepper motor though, adding guide pullys at the four corners with the belt attached to both ends of the x axis and travelling arounf the whole structure would keep both sides in sync."
How the hell should that ever work!
Just goes to show you when thinking of other things one shouldn’t be typing about another.
I’ve tried the G Code option that was put up here while yes it does work I have the same problem with the pen being up when it should be down and down when it should be up not sure why this is occurring at least I can play with the code to reverse the pen position.

Chris

#6

Hi Chirs,

I will ask my workmate about you problem and and give you an answer soon.

So sorry about the delay.

#7

Eric, any solutions to the issue?
Updates to the App?
I’m waiting patiently, but I have a plotter here that I can’t play with, and Money that so far I don’t feel was well spent.

Chris

#8

I have bought the same kit. Here are some suggestions:

  • You can add few plastic rings to extend linear motion shafts and to dramatically reduce wobbliness of the system and straighten up the whole thing (I’ll try to make a photo when I get home);
  • You can cut a part of a cable from one motor to add to the other one, to solve the issue with too short wires;
  • To stop the solenoid from jumping all the time and making “dot art”, you can change the distance check on line 128 in the XY_plotter.ino to raise the pen when distance exceeds one - two thousands (2000 works fine for me, but it might not raise the pen on some very short distances where it should).
  • Getting one really sharp pen, reducing speed below 20 and checking “high precision” checkbox should help too.
  • You can reduce step mode from 1/8 to 1/16 to make nicer looking, but smaller images.
#9

Hakim, thanks for responding.
I thought of the spacer trick too, just haven’t tried it yet.
I will try all of your suggestions, greatly appreciated.

Avtech

#10

After a bit more testing here is what I found out:

  • Distance check in XY_plotter.ino seems to work best when it set to 700 (line 128 in the source code)
  • To avoid overheating of the solenoid “analogWrite(motorPwm, 200);” should be replaced with “analogWrite(motorPwm, 70);”
  • The speed in the Android application should be 15
  • Sharp marker (pen) works when motor driver’s step mode is set to 1/16, but with the standard 1/8 the resulting image looks better with thick marker.
  • If you choose a custom image for the Android app to draw, the image has to have exactly the same width and height plus the maximum width/height can not exceed 640px, otherwise the app will most likely crash.
  • Both the Android app and the Arduino code is more of a temporary hack than anything suitable for end user. The way Android app works is that it just takes pixels in the image instead of trying to convert image to a path and depending on the set speed and the set precision it skips more or less pixels - it doesn’t actually change the speed of the motor (which results in pretty bad pictures with high speed). Also because the Android app sends the actual steps to the Arduino app and not just coordinates that should be interpreted by the Arduino app, the amount of data to be sent becomes pretty big and the whole drawing becomes pretty choppy. Moreover as most probably noticed the Android app is really crash prone and just switching the orientation of the phone stops the drawing process. For those interested here is the source code of the Android app -> https://www.dropbox.com/s/u9qiuqm9pnwo7sc/XY%20Stage%20Android%20App%20Source%20code.rar .

And here are some images I forgot to post the last time:

I’ll upload a video showing a timelapse of the drawing when I have some time for it.

#11

@hakim Thanks for your testing,now there is the source code on Github and it can be built by Intellij Idea.

#12

Thanks. I’ll try to improve it at some point.

#13

Hey Chris,

Me and my friend(both 14) were making a XY Plotter and we had the HackerSpace Kit. That kit didn’t have all the necessary Stuff to build a XY Plotter, but we managed to build it and our teacher got us a few stuff like the Me Bluetooth. We were working on this for 2 months with no instructions what so ever, Only a Picture. I found it weird how no one has posted the Me Bluetooth pin(1234), and that there isn’t a Video Tutorial… The Pen in the XY Plotter is controlled by a solenoid.
Best Regards,
Kamran

P.S: For MakeBlock Admins where can I get one of those custom pens that change colors or is that just u guys changing the pens?

#14

@Kamcorder123

Hi Kamran,

If you want to build a XY Plotter, kindly advise you can purchase the XY-Plotter here.
And if you want to custom pens, you can buy the colorful pens in local place just instead of original pen would be okay.

Christina

:

#15

My teacher bought us that kit thats how we got the bluetooth and stuff. for some reason we it didn’t come with instructions either… We got the 2 pens, but I was wondering if there was a pen or something we could program to change colors. or does it not exist?

#16

hi Kamcorder123,you could make a struct like microscope for changing pen.

800px-Loupe-binoculaire-p1030891.jpg800x600 57.8 KB

#17

Is that what you guys use? Is there a product like that? I don’t think my science teacher will be happy to give me a microscope… It would be better if it was a product that we could program, this would be a little difficult but doable.

#18

@Kamcorder123 Nah, we don’t use this. @indream means you can build the similar-structure, the microscope in this picture for your reference.

#19

Hi there,

I too have some problems with my xy-kit.
It seems like the Stepper for the Y-axis is not powerfull enough. It just rattles and the motor seems to loose steps.

I already checked the mechanics of course, but i think it’s sliding easely enough. Although i think the Linear Motion units are poor quality. I will replace the inner parts with better ones.

Does any of you guy’s have any idea?

Thanks

#20

Hi hr_maurer,
Does this motor behave like the other when not powered? When you turn it by hand without powering it, does it sound the same as the others? One of my steppers had a mechanical problem and it was actually very audible when I turned it. Makeblock is now sending me a replacement.

Also: how much power are you supplying to the setup? Keep in mind that each motor can pull more than 2A if allowed to do so. If there is not enough power, the steppers will appear to be “weak”.