Hi friends! I will show you how to build and use a plotter to draw vector or polar plotter images in this project. A polar graph machine uses two centered coordinates to generate drawings using a pen suspended on belts attached to two pulleys above the drawing surface.

I will start this project by first printing the necessary 3D parts and building the structure of the plotter, and then I will continue with the electronics and software part later in the project.

Due to the large size of the source code, we will use an Arduino UNO board based on Atmega328P and a ULN2003 motor driver for the stepper motors. You can build the circuit on a breadboard, but as you know I prefer to design a printed circuit board for a more professional prototype.

I share my printed circuit board designs as open source on PCBWay's project sharing page, where you can easily order the printed circuit boards I use in my projects, both assembled and empty PCBs. You can choose PCBWay for low-budget and high-quality printed circuit boards.

After soldering, I checked that the circuit board was working smoothly by uploading a simple stepper motor code at this stage. Then we continue the project by mounting the circuit board on the panel.

Our panel is almost ready, but first I printed 4 legs using a 3D printer and assembled them to make the panel stand. 

At this stage, I add a paperclip to the servo motor arm for the control of the pen. Then, by uploading a simple servo motor code, I obtain the minimum and maximum angle of the servo arm. Thus, we have obtained the required angle range for the pen to touch down and up to the panel surface.

Before the programming step, I added a few more nuts to both belts and bearings to the gondola to make the pen more stable. Finally, I attached a drawing page to the panel surface.

In the source code section, first download and install the previous version of the Arduino code editor, 1-8-5. Polar graph code is more stable and without errors in this version.

When you first run the Arduino code editor, you will see that the Sketchbook section is still empty. First, go to the preferences, and keep your Sketchbook location in mind, then exit the code editor. After that, download the shared source code folder and copy the Arduino libraries inside it, go to your Sketchbook location and paste them into the Arduino libraries folder. Then go back to the shared source code folder and copy and paste the Arduino Polar Graph Server folder into the Arduino folder in your Sketchbook location. When you re-open the Arduino code editor, you will now see the Polar Graph Server code in the Sketchbook section. Open the Polar Graph server code, the important point here is that I have updated the “Configuration” section according to the current project components and shared the updated code with you.

I do not recommend making changes, but you can update the stepper motor direction pins if your motors move in the opposite direction. Now we can upload the code to the board, select the board type and the port it is connected to, and then press the upload button.

Once the upload is complete, open the Serial Monitor and update the Baud Rate to see if the code is executing correctly, if everything is okay you will get a “ready” message as shown on the screen. That's it for the Arduino source code, now let's move on to the Polar Graph software.

The Processing editor is required to run the Polar Graph software. Go to Processing and download version 2-2-1, then move the downloaded Processing folder to your “My Documents” location and run Processing, you will be given a message to “Create a Sketchbook folder”, and click “Done” to complete the installation.

When the editor opens you will again see that the Sketchbook section is empty, go to properties find your Sketchbook location, and exit the editor. Then go to the shared source code folder and copy the Processing libraries, then go to Processing's Sketchbook location and paste them into the libraries folder. Turn to the shared source code folder and copy the Polar Graph controller folder, then paste it into your Processing Sketchbook location. Run the Processing editor, go to the Sketchbook section, and open the Polar Graph code. You don't need to make any changes, just run the code, you may get a warning message, but after giving the necessary permissions the Polar Graph software will run.

Polar Graph opens with default properties and contains three main elements in the interface. The control panel with all buttons on the far left, the middle part, the gray rectangle representing the machine itself, and the command queue on the right side of the machine. You can zoom in and out of the machine surface using the scroll wheel of the mouse and you can “grab” and move the machine surface using the middle mouse button.

The setup section is used to define the machine configuration. I'm uploading my already-defined setup file for this project, and I've shared this configuration file with you. As you can see, when I uploaded the file, the dimensions of the machine and the page area changed.

There is a Home Point on the machine, this represents the starting point of the pen. This is also the starting point of the page. The Page and Home position of the project is approximately 120 millimeters. To find this value, place a horizontal line between the two motor gears and a vertical line 120 millimeters down from the midpoint of this line, the point where the vertical line ends is where you will place the pen. After placing the pen and updating the value, don't forget to press the Center Page and Center Home point buttons.

Here we update the Servo motor angles we obtained earlier for pen down and pen up movement. Then we make the serial connection of the board. If the connection is successful, you will see that the Connection message turns green and the machine is ready. Then I start the command queue by clicking on it so that every change I make will be sent to the machine directly. Now, to test that the servo positions are working correctly, I first send the lift range to the machine, then press the Test Lift Range button and observe that the servo motor and pen movement are working correctly. If you have built a different machine, you can update the required values via these buttons. If you make changes, send the machine settings to the machine and save your settings. 

We are in the Input section, the purple circle on the screen symbolizes the pen, the point where the pen is located is defined to the machine by pressing the Set Home and Set Pen Position buttons.

If you want to test that the motors are moving in the correct direction, you can use the Move Pen to Point button. By selecting the point on the page surface where you want the pen to move, you can observe the motor and pen movements.

Using the Return to Home button, you can move the pen back to the Home point. This will confirm that the pen has correctly reached the home point.

The machine is working correctly and properly on the hardware side. Now let's look at the drawing side, you can upload an image file and enter Polar Graph settings to create Polar Graph images. However, creating a Polar Graph image is a bit complicated and requires some knowledge. For now, I will show you how to create a vector drawing.

Load the image with the Load Vector button, then move the image to the drawing area with the Move Vector button. Adjust the image size with the Resize Vector button, then select the drawing area with the Select Area button and define the drawing area with the Set Frame to Area tool.

Finally, click the Draw Vector button, and when you look at the command queue, you will see that the drawing has started. We have come to the end of another project, I hope it was a useful project for you.