Problem of a moving circle Interface which corresponds to position XY data provided by Arduino

thanhvu94

Hello everyone,

I'm writing a Processing program displaying a circle which will move according to the X Y position data received from Arduino. However, the problem is that the circle movement doesn't seem to work as I expected (when I move, I have to wait 5 6 seconds later to see the circle really moves slowly. Moreover, the circle always disappears and then appears quickly again, which is annoying to my eyes).

I post my Processing code below, and if you find any problem (due to buffer, background or anything), or if you have a better approach/solution for my objectives, please tell me. I send 2 float data (with 4 floating digits), at baudrate 115200 in Arduino DUE.

Code Processing:

    // import libraries
    import java.awt.Frame;
    import java.awt.BorderLayout;
    import processing.serial.*;

    // Serial port to connect to
    String serialPortName = "COM3";
    float[] x= new float[2];
    float xf;
    float yf;
    /* SETTINGS END */

    Serial serialPort; // Serial port object


    void setup() {
      size(900,900);
      background(51);
      noStroke();
      //frameRate(100);
      serialPort = new Serial(this, serialPortName, 115200); 
    }

    void draw() {

      if (serialPort.available() > 0) {
        byte[] inBuffer = new byte[30]; // holds serial message
          try {
            serialPort.readBytesUntil('\r',inBuffer);
          }
          catch (Exception e) {
          }
        String myString = new String(inBuffer);
        String[] nums = split(myString,' ');
            try {
                x[0] = float(nums[0]);
                x[1] = float(nums[1]);
            }
            catch (Exception e) {
            }    
      //Calculate x and y position based on data sent by Arduino
        xf = 1.508*tan((3.14/180)*(121*x[0]+61*(x[0]*x[0])+35*x[1]-171*(x[1]*x[1])+1.7));
        yf = 1.508*tan((3.14/180)*(-290*x[1]-799*(x[1]*x[1])+20*x[0]+39.2*(x[0]*x[0])-7.1));
      background(51);
      //The value of xf and yf is normally very small, so I multiply them with a value so I can actually see them moving in the Processing screen
          ellipse(xf*1000+450, yf*1000+450, 40, 40);
      }
      }

Thank you.

GoToLoop

https://forum.Processing.org/two/discussion/12757/transmission-of-a-float-through-a-serial-link#Item_7

kfrajer

I am not sure why you have try-catch blocks there if you are still processing and generating values for xf and yf. Check the examples provided: https://processing.org/reference/libraries/serial/index.html

I suggest implementing the changes below in your code (also follow GoTo's link).

Related to your last operation, you said that you are multiplying your values by a factor so to be able to see motion. If you describe the nature of your values (description, where they come from and how you use them in Processing) then I could provide a relevant sample code using the map() function instead: https://processing.org/reference/map_.html

Kf

    void draw() {

      if (serialPort.available() > 0) {
        byte[] inBuffer = new byte[30]; // holds serial message

        serialPort.readBytesUntil(ENTER, inBuffer);

        if (inBuffer==null) {
          return;
        }

        String myString = new String(inBuffer);
        String[] nums = split(myString, ' ');

        if (nums.length==2) {
          x[0] = float(nums[0]);
          x[1] = float(nums[1]);

          //Calculate x and y position based on data sent by Arduino
          xf = 1.508*tan((PI/180)*(121*x[0]+61*(x[0]*x[0])+35*x[1]-171*(x[1]*x[1])+1.7));
          yf = 1.508*tan((PI/180)*(-290*x[1]-799*(x[1]*x[1])+20*x[0]+39.2*(x[0]*x[0])-7.1));
          background(51);
          //The value of xf and yf is normally very small, so I multiply them with a value so I can actually see them moving in the Processing screen
          ellipse(xf*1000+450, yf*1000+450, 40, 40);
        }
      }
    }

thanhvu94

I found out my problem. It is because I start my Arduino first and then I start my Processing IDE after a while. Since the Processing will collect all the data from the beginning (when Arduino starts) so my position data when I move is not real time (several seconds delay).

Is there any way to put a code in Arduino that says "just start the Arduino program when I click button "Run" in Processing?" or something like that to solve my problem above?

I'm using Arduino DUE.

Thanks

RichardDL

That's not the way. Make Processing start by throwing away all that has already arrived. Let's continue this in your later thread. https://forum.processing.org/two/discussion/22602/processing-interface-stops-after-playing-for-2-3-minutes#latest