Sending serial data to Processing

Question

I have a question about using the Arduino and Processing. I want to build a touch sensor using aluminum foil and connect it to an interface built in Processing. However i've come across a problem. I don't know how to send the serial data from the Arduino to Processing. This is the code I'm using to get the sensor value from the aluminum foil:

#include <CapacitiveSensor.h>
CapacitiveSensor cs_4_2 = CapacitiveSensor(4,2); 
void setup(){
 Serial.begin(9600);
}
void loop(){
 long start = millis();
 long total1 = cs_4_2.capacitiveSensor(30);
 Serial.print(millis() - start); 
 Serial.print("\t"); 
 Serial.print(total1); 
 Serial.print("\t"); 
 Serial.print('\n');
 delay(100); 
}

The foil is connected to dig pin 4 with a resistor of 1M in between and to dig pin 2 with a resistor of 1K. Pin 4 is the send pin, pin 2 is the receive pin. It all works just fine, in the serial monitor in the Arduino software I get the value of the time between refreshes and the sensor value. But how do I use this sensor value in a Processing sketch? I thought of maybe using Firmata on the Arduino, but then I wouldn't know how to use the CapacitiveSensor library and get the sensor values. Does anyone know how to get this to work? Help would be greatly appreciated!

Answer 1

Try to use this code:

// Graphing sketch
import processing.serial.*;
Serial myPort; // The serial port
int xPos = 1; // horizontal position of the graph
void setup () {
// set the window size:
size(400, 300); 
// List all the available serial ports
println(Serial.list());
// I know that the first port in the serial list on my mac
// is always my Arduino, so I open Serial.list()[0].
// Open whatever port is the one you're using.
myPort = new Serial(this, Serial.list()[0], 9600);
// don't generate a serialEvent() unless you get a newline character:
myPort.bufferUntil('\n');
// set inital background:
background(0);
}
void draw () {
// everything happens in the serialEvent()
}
void serialEvent (Serial myPort) {
// get the ASCII string:
String inString = myPort.readStringUntil('\n');
if (inString != null) {
// trim off any whitespace:
inString = trim(inString);
// convert to an int and map to the screen height:
float inByte = float(inString);
inByte = map(inByte, 0, 1023, 0, height);
// draw the line:
stroke(127,34,255);
line(xPos, height, xPos, height - inByte);
// at the edge of the screen, go back to the beginning: 
if (xPos >= width) {
xPos = 0;
background(0);
}
else {
// increment the horizontal position:
xPos++;
}
}
}

Also look at: http://www.arduino.cc/en/Tutorial/Graph

Answer 2

SparkFun has a tutorial where they explain in great detail how to create a project where your Arduino communicates with Processing on your PC.

Answer 3

You're already half way there - you're sending the data from the Arduino. All you need to do now is read up on how to use Serial in Processing (hint: Arduino is based on Processing, so you should already know most of it) in order to read what you're sending.