I broke down the setup a while ago since I was not getting the motion I desired. The setup consists of 4 motors (I originally used wormgears for simplicity), 3 motors have circular plywood of about 10 inches diameter connected with a pivot to hold an aluminium frame that connects to a pen eventually. The 4th motor has 12-square-inch plywood attached, this is the plywood that caries my drawing paper so there may be some extra weight from the pen.
When I previously used the warm gear, I could not achieve the very slow motion I needed without the platform going back and forth.
can you post a picture. I don't have a clear imagination of your machine from the word-description
I originally used warm gears which did not work well for the motor carrying the plywood for drawing (I did not use arduino, I connected to some motor driver I bought on amazon). I even switched to one with a low rpm and it was just jerking at a low rpm which is why I considered a stepper motor.
Here is a schematic of the machine. I hope it is clear enough. I need motor 1 to be able to move extremely slow (you will need to stare at it for a while to notice the motion) while the other motors will be moving faster (can slow them down, vary the speed or stop one of them to investigate the effect on the drawing). This is an idea I began exploring in my generative art class.
I am hoping to set it up such that I can easily disconnect the control panel for transport to school or where ever I need to show it.
I was able to figure out how to make this setup here work the way I want it to work for motor 1 above. However, the PWM controller buttons (CW, CCW and stop) are in weird positions (the red buttons) so I will not be able to set up a functional panel. Also, I want to avoid having a bulky setup.
Hi,
So motors 2, 3, and 4 drive a disk with the arm pivoting on an offset pin?
Have you made a simple model without motors to see if you will get satisfactory motion?
Mechanical dimensions will be fairly critical and I doubt from your diagram that most of the 2, 3, or 4 motor will be able to complete a full 360Deg rotation because of the arm dimensions and rotary positions of the other motors.
Tom.... 
You could wire your own button switches in parallel with the buttons on the PWM controller and put your buttons anywhere.
motors 2, 3 and 4 will complete the 360-degree rotation, the relative motion is what is needed to create the drawing on motor 1.The arms are pivoted together.
This would mean that I get to use 4 stepper motor controllers which I do not have the space for. I also do not have experience with electrical components, this is one reason I am considering using Arduino with the controllers so I that I would only deal with connecting cables and at best try to figure out the code to make my setup work.
Here is a link to a similar machine, this person used 3 stepper motors. All motors will be able to move freely irrespective of the other motor/rod placement because of the pivot on the aluminium rod.
Sorry but that is a two arm unit, adding extra stepper and having FIVE interconnected arms the way that you have means you need to do some measurements and make a simple model, even card board, to see if you have your config correct.
You are constraining BOTH ends of each arm.
The example has only one end of each of the TWO arms constrained.
Tom....
The constrain has a pivot and the connected arms will be only forced to move around those pivots. It will have 360-degree motion. I would expect the arms to rotate around one another as in the attached photo.
Here is a more similar machine as I am gunning for.
Hi,
But that is not what you have, adding arms and moving drive points from that example does not mean it will work the same or allow all the motors to turn 360Deg at all times.
You will need to experiment on moving your motors, moving your pivot points and adjusting the arm lengths.
I would say it has taken Robert Balke Zeichenmaschinen quite a bit of work to get what he has.
What is to stop you using the stepper motor and driver you have now, but 4 times and get a prototype going, forget about size and space it occupies, just get a proof of concept going.
Then when you have it performing to your requirements, then think about size.
Why do you want to make the controller small when you have such a large operating table?
Tom...
PS. Get your mechanical hardware built and working, then think of a micro-controller.
Thank you for your response once more. As mentioned earlier, I already tried a setup using worm gears and it works fairly ok (the drawing platform needed a lot of help, which is when I started looking at stepper motors). The table I have is not large enough for 4 big drivers like the DM542T, the alternative will be to mount the drivers under the table but I work in my apartment living room area and have to place the plywood on a surface. The image below is one of the drawings I made before breaking down my setup and as you can see, there is an anomaly at the lower right part of the drawing. This was because the drawing table froze.
I could also say that I got some pretty results too but those results were not consistent which is why I started over again and I think I am too invested in this to change my project. I already got some items that are not returnable and as an international student, I can only spend so much on what I want to show the class/department. However, I intend to see this through and maybe go on to make something out of it.
Here are some images I got that I think are nice....
Edit: I need the motors to make the hardware (the arms are seating on the motors)
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.