使用处理读取Arduino int数组

Question

I have an arduino-processing communication problem. I have arduino code that gives me X-and/Y coordinates from a touchScreen and it works well, no problem with that, I got my X- and Y coordinates. BUT I need to visualize that, I am trying to write code in Processing 3.0, so that I will be able to see on my computer, where the touchFolie was being touched. So I need to send the xy from arduino to processing so that I will be able to draw. Does anyone know how can I send an integer array[X,Y] from arduino to processing ??

Answer 1

It will be helpful to have a play with the Serial library in Processing and the SerialRead example (in Processing > File > Examples > Libraries > serial > SimpleRead )

Let's say you're starting from scratch. To send data from Arduino you need to open a Serial connection. At this stage the only important details is the baud rate: how fast is the data flowing.

Here's a minimal Arduino data out example:

void setup() {
  //initialize the Serial library with baud rate 115200
  Serial.begin(115200);
}

void loop() {
  //write data to the serial port
  Serial.println("test");
  delay(1000);
}

If you open Serial Monitor in the Arduino software and set the baud rate to 115200 you should see test printed once a second.

To read the same data in Processing, aside from specifying the baud rate, you must also specify the serial port (what you have selected in Tools > Port and is also listed at the bottom right of your current Arduino sketch):

import processing.serial.*; 

void setup() { 
  //update the serial port index based on your setup
  println(Serial.list());
  Serial arduino = new Serial(this, Serial.list()[0], 115200); 
  arduino.bufferUntil('\n'); 
} 

void draw() { 
} 

void serialEvent(Serial p) { 
  //read the string from serial
  String rawString = p.readString();
  println(rawString);
}

Notice that we tell Processing to buffer until it reaches a '\\n' character so we don't have to worry about waiting for every single character and append it manually to a String. Instead using bufferUntil() , serialEvent() and readString() most of the work is done for us.

Now that you can send a String from Arduino and read it in Processing, you can do some String manipulation, like splitting a string into multiple using a separator via the split() function:

String xyValues = "12,13";
printArray(xyValues.split(","));

The last part would be converting the split values from String to int :

String xyValues = "12,13";
String[] xy = xyValues.split(","); 
printArray(xy);
int x = int(xy[0]);
int y = int(xy[1]);
println("integer values: " + x + " , " + y);

So, in theory, you should be able to do something like this on Arduino:

int x,y;

void setup() {
  //initialize serial 
  Serial.begin(115200);
}

void loop() {
  //simulating the x,y values from the touch screen, 
  //be sure to replace with the actual readings from 
  //NOTE! If the screen returns values above 255, scale them to be from 0 to 255
  x = map(analogRead(A0),0,1024,0,255);
  y = map(analogRead(A1),0,1024,0,255);
  //write the data to serial
  Serial.print(x);
  Serial.print(",");
  Serial.print(y);
  Serial.print("\n");
}

then on the Arduino side:

import processing.serial.*; 

float x,y;

void setup() { 
  size(400,400);
  //update the serial port index based on your setup
  Serial arduino = new Serial(this, Serial.list()[0], 115200); 
  arduino.bufferUntil('\n'); 
} 

void draw() { 
  background(0); 
  ellipse(x,y,10,10);
} 

void serialEvent(Serial p) { 
  //read the string from serial
  String rawString = p.readString();
  //trim any unwanted empty spaces
  rawString = rawString.trim();
  try{
    //split the string into an array of 2 value (e.g. "0,127" will become ["0","127"]
    String[] values = rawString.split(",");
    //convert strings to int
    int serialX = int(values[0]);
    int serialY = int(values[1]);
    //map serial values to sketch coordinates if needed
    x = map(serialX,0,255,0,width);
    y = map(serialY,0,255,0,height);
  }catch(Exception e){
    println("Error parsing string from Serial:");
    e.printStackTrace();
  }
}

Note The Arduino code above will probably not solve your problem as it is, you need to integrate your touch sensor code, but hopefully it provides some hints on how you can tackle this.

Sending a String, then parsing it is one approach, but not the most efficient. If you have your x,y values in a 0-255 range, you could send just 2 bytes (each coordinate as a single char ) instead of up to 8 bytes, but for now it may be much easier to play with Strings rather than jump into bytes straight away.

Answer 2

This tutorial will help you. 5 minutes and you are able to connect each others!

EDIT:

First of all look the first part of the tutorial ("From Arduino..." "...To processing"). In arduino you have just to send your coordinates in your Serial.

Serial.println(coordX);
Serial.println(coordY);

In processing you receive this coordinates as Text but you are able to convert it in Float with parseFloat() function.

This is the code you need in Processing to receive your coordinates and store them in variables.

    import processing.serial.*;
    Serial myPort;  // Create object from Serial class
    String val;     // Data received from the serial port

    float x = 0;
    float y = 0;
    boolean first = true;
    setup() {
       String portName = Serial.list()[0]; //change the 0 to a 1 or 2 etc. to match your port
       myPort = new Serial(this, portName, 9600); 
    }
    void draw() {
      if ( myPort.available() > 0) {  // If data is available,
         val = myPort.readStringUntil('\n');         // read it and store it in val
         if (first) {
            x = parseFloat(val);
            first = false;
            println("x= "+val); //print it out in the console
            } 
         else {
             y = parseFloat(val);
             first = true;
             println("y= "+val); //print it out in the console
             }
      }

I hope this will help you solve your problem.