controlling 2 servo rotation via mouseClick in processing

Projects Interfacing w/ Software on the Computer
1

hey everyone,

as i am working on a project, I encountered a problem with servo+processing.

i want to make a quick processing sketch that allows me click my mouse to send the XY position of the mouse to the arduino, so that the servo on the arduino can rotate correspondingly.

I can run the arduino code and type the coordinates from the serial monitor. but it doesnt work when I run the processing sketch to send the coordinates. the code of the processing seems have some problem at write() function. could you please have a look of it?

thank you !

====================here is my arduino code====================

#include <Servo.h> 


const int NUMBER_OF_FIELDS = 2; // how many comma separated fields we expect
int fieldIndex = 0;            // the current field being received
int values[NUMBER_OF_FIELDS];   // array holding values for all the fields
int pos[NUMBER_OF_FIELDS];
int posX = 90;
int posY = 90;

Servo myservoP;
Servo myservoT;

void setup() 
{ 
  Serial.begin(9600);
  myservoP.attach(9); 
  myservoP.write(90);
  myservoT.attach(10); 
  myservoT.write(90);

} 

void loop() 
{ 
  if (Serial.available()){

    char ch = Serial.read();
    if(ch >= '0' && ch <= '9') 
    {
      values[fieldIndex] = (values[fieldIndex] * 10) + (ch - '0'); 
    }
    else if (ch == ',') 
    {
      if(fieldIndex < NUMBER_OF_FIELDS-1)
        fieldIndex++;  
    }
    else
    {
      Serial.print( fieldIndex +1);
      Serial.println(" fields received:");
      for(int i=0; i <= fieldIndex; i++)
      {
        pos[i] = values[i];        
        values[i] = 0; // set the values to zero, ready for the next message
        Serial.println(pos[i]);
      }
      myservoP.write(pos[0]);
      myservoT.write(pos[1]);
      fieldIndex = 0; 

    }
  } 
}

====================here is my processing code====================

import processing.serial.*;

Serial port;
int valX, valY;
float val1, val2;

void setup() {
  size(800, 600);
  background(255);
  println(Serial.list());
  port = new Serial(this, "COM3", 9600);
}

void draw() {

}

void mouseClicked(){
   val1 = map(mouseX,0,800,0,179);
   val2 = map(mouseY,0,600,179,80);
     valX = int(val1);
  valY = int(val2);

  port.write(valX+','+valY);
}
2

Your Processing code is sending something like "120,84".

Your Arduino code just reads each character that comes in ('1', '2', '0', ',', '8', and '4'), and manipulates values[n], if the character is a digit. If the character is a comma, it increments the array index. If the character is not a digit and not a comma (a carriage return, a space, a line feed, etc.), it shows what it received.

When you send data from the Serial Monitor, you send something like "120,84". The carriage return and line feed are not digits and not commas, triggering the end of packet processing that does not happen when Processing sends the data.

Hopefull, you will see what you need to have Processing do.

3

hey paulS
thanks for the quick reply.

I modified the write() function in processing as follow

port.write(valX+","+valY+"\n");

now it works fine:)

after that I tried to continuously sending the XY position of my mouse to the servo so that the mouse and the servo are synchronized. but they are weirdly shaking all the time.

do u think it is becoz the data stream is too much for arduino?

thank you!

4

do u think it is becoz the data stream is too much for arduino?

No, I think it is because the data needs so much processing on both ends. The Processing application needs to convert two byte-sized values to strings, and send as many as 8 bytes.

Then, the Arduino needs to read those 8 bytes, and convert them back to (byte sized values in) ints.

Also, all the debugging output means that there is the possibility of loosing incoming data while sending debug output.

The first thing I'd do is comment out the debug output and see if that makes the problem go away.