Hello,

I am working on the same problem, principaly to pass 8 sensors analog information from Arduino to processing and 3 stepper information from processing to Arduino.

in Arduino I have this program (here for two sensors, but easy to use with 6):

void setup()
{
 Serial.begin(9600);
}

void loop()
{
 int Sensor = analogRead(0);
 Serial.print("a");
 decomp(Sensor);
 Serial.println();
 Sensor = analogRead(1);
 Serial.print("b")
 decomp(Sensor);
 Serial.println();
}

void decomp(int Sensor){
 int val0 = Sensor / 1000;
 Serial.print(val0);
 Sensor = Sensor % 1000;
 int val1 = Sensor /100;
 Serial.print(val1);
 Sensor = Sensor % 100;
 int val2 = Sensor / 10;
 Serial.print(val2);
 int val3 = Sensor % 10;
 Serial.print (val3);
}

in Processing, I have this one:

import processing.serial.*;

Serial myport;
int val0 = 0; //variable fo units, tens etc.
int val1 = 0;
int val2 = 0;
int val3 = 0;
char val4; //letter tag
int val5 = 0; //variable for 10 and 13 ASCII
int val6 = 0;
int vala; //variable for each sensor
int valb;
int valc;
int vald;
int vale;
int valf;

void setup() {
 size(400,400);
 frameRate(25);
 myport = new Serial(this, Serial.list()[0], 9600);
}

void draw() {
 background(0);
 if (0 < myport.available()) {  // If data is available,
   val5 = myport.read();         // read it and store it in val5
   if (val5 ==13){ //new line
     val6 = myport.read(); //carriage return
     val4 = myport.readChar(); //letter tag
     println(val4); //for test purpose
     val0 = myport.read() - 48; //48 is ASCII value of 0
     println(val0); //thousands
     val1 = myport.read() - 48;
     println(val1); //hundreds
     val2 = myport.read() - 48;
     println(val2); //tens
     val3 = myport.read() - 48;
     println(val3); //units
     int valT = (val0 * 1000) + (val1 * 100) + (val2 * 10) + val3
       switch (val4){
     case "a":
       vala = valT;
     case "b":
       valb = valT;
     case "c":
       valc = valT;
     case "d":
       vald = valT;
     case "e":
       vale = valT;
     case "f":
       valf = valT;
     }
   }
 }
}

The strange is that work, when I start the program, I read the good value, but not changing in real tim when I move the pots. But if I stop and start the program, the value are updated. When I receive the serial flow in Arduino or in goSerial app, the values are updated in real time.

Perhaps my project can help you? perhaps someone have an idea of what is wrong?

My goal is to use it to obtain accurate information in Isadora, for the moment I use a Max/Msp patch, working well in both way, but I want to use processing for educational/licence reasons.

Thank you in advance

First, let me recommend "Making Things Talk" by Tom Igoe.

Now, a good way to send data between processing and arduino is by constructing a simple protocol with strings. You'll need each value you're passing, a delimiter to separate the values, and either a header or a footer to know when you're packet is finished. In the example, I'm using a comma as a delimiter and a pipe as the footer. Processing reads data until it reaches the footer and then uses the delimiter to tell the input values apart. You'll still want to set up communication so that each side waits for the other to finish talking.

//construct a message with multiple values in arduino
//we can't just send a string from here since it only officially understands 'bytes'
Serial.print(value1, DEC);
Serial.print(",");
Serial.print(value2, DEC);
Serial.print(",");
Serial.print(value3, DEC);
Serial.print("|");

//read the message in Processing
void serialEvent(Serial myPort){
 String myString = myPort.readStringUntil(124); //the ascii value of the "|" character
 if(myString != null ){
   myString = trim(myString); //remove whitespace around our values
   int inputs[] = int(split(myString, ','));
   //now assign your values in processing
   if(inputs.length == 3){
     var1 = inputs[0];
     var2 = inputs[1];
     var3 = inputs[2];
   }
 }

}

David Wicks wrote on Nov 26^th, 2007, 3:58pm:


I'm trying to use Wicks' example above to take data from two potentiometers and use the numbers as x and y coords to move a square around on the screen.  It seems like the split is working, but I wind up with an array with a correct value for the first pot and a 0 for the second one regardless of what the value actually should be.  I know that the data string inRead was definitely read in and was not changed.  Just something seems to be not working with the array.  

Any ideas

I'm running:

Arduino v 0009 Alpha
Processing v 0135 Beta
Mac OSX 10.4.11

The problem is that processing has some problems  with the char "|", so what is necessary is just adding a  comma "," after the second value that you want to send  to processing like this:

valor1 = analogRead(2)/4;
valor2 = analogRead(3)/4;
Serial.print(valor1,DEC);
Serial.print(",");
Serial.print(valor2,DEC);
Serial.print(",");
Serial.print("|");

Then in processing, discard the tird value, the comma ",".
It worked for me
Regards
CAL

Is it possible to do this the other way, i.e. send a string to the arduino from processing, read it as a string and then separate it into 3 values?

Not sure of the code on the arduino side for this...anyone?

First, let me recommend "Making Things Talk" by Tom Igoe.

Now, a good way to send data between processing and arduino is by constructing a simple protocol with strings. You'll need each value you're passing, a delimiter to separate the values, and either a header or a footer to know when you're packet is finished. In the example, I'm using a comma as a delimiter and a pipe as the footer. Processing reads data until it reaches the footer and then uses the delimiter to tell the input values apart. You'll still want to set up communication so that each side waits for the other to finish talking.

//construct a message with multiple values in arduino
//we can't just send a string from here since it only officially understands 'bytes'
Serial.print(value1, DEC);
Serial.print(",");
Serial.print(value2, DEC);
Serial.print(",");
Serial.print(value3, DEC);
Serial.print("|");

//read the message in Processing
void serialEvent(Serial myPort){
String myString = myPort.readStringUntil(124); //the ascii value of the "|" character
if(myString != null ){
  myString = trim(myString); //remove whitespace around our values
  int inputs[] = int(split(myString, ','));
  //now assign your values in processing
  if(inputs.length == 3){
    var1 = inputs[0];
    var2 = inputs[1];
    var3 = inputs[2];
  }
}

}