Hi,

I have a similar problem. But using ping))) ultrasonic sensor instead (digital).

I don't know what you are doing wrong (still learning), but am curious how to connect arduino and processing.

M

Well consider the fact that your Arduino code is running a loop and in Processing setup() is called only once.  Try the following Processing code and see what happens when you hold a key down (untested):

1. import processing.serial.*;
2. Serial port; 
3. void setup() {
4.   port = new Serial(this, Serial.list()[1], 9600);
5.   port.write(000255000);
6. }
7. void draw() {
8. }
9. void keyPressed() {
10.   port.write(000255000);
11. }

Thank you. It helps understanding the procedure.

However, my code is a bit different (below). I'm using ping example from Arduino webstie and would like to capture the distance (inches or centimeters). Then I'd like to use these values for a cool graphics in Processing. It works nicely in arduino's serial monitor, but as I said...would want to capture data and draw it in Processing.

How would you draft a code in Processing to read this Arduino code:

1. /* Ping))) Sensor
    
      This sketch reads a PING))) ultrasonic rangefinder and returns the
      distance to the closest object in range. To do this, it sends a pulse
      to the sensor to initiate a reading, then listens for a pulse
      to return.  The length of the returning pulse is proportional to
      the distance of the object from the sensor.
       
      The circuit:
       * +V connection of the PING))) attached to +5V
       * GND connection of the PING))) attached to ground
       * SIG connection of the PING))) attached to digital pin 7
   
      http://www.arduino.cc/en/Tutorial/Ping
     
      created 3 Nov 2008
      by David A. Mellis
      modified 30 Jun 2009
      by Tom Igoe
    
      This example code is in the public domain.
   
    */
   
   // this constant won't change.  It's the pin number
   // of the sensor's output:
   const int pingPin = 7;
   
   void setup() {
     // initialize serial communication:
     Serial.begin(9600);
   }
   
   void loop()
   {
     // establish variables for duration of the ping,
     // and the distance result in inches and centimeters:
     long duration, inches, cm;
   
     // The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
     // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
     pinMode(pingPin, OUTPUT);
     digitalWrite(pingPin, LOW);
     delayMicroseconds(2);
     digitalWrite(pingPin, HIGH);
     delayMicroseconds(5);
     digitalWrite(pingPin, LOW);
   
     // The same pin is used to read the signal from the PING))): a HIGH
     // pulse whose duration is the time (in microseconds) from the sending
     // of the ping to the reception of its echo off of an object.
     pinMode(pingPin, INPUT);
     duration = pulseIn(pingPin, HIGH);
   
     // convert the time into a distance
     inches = microsecondsToInches(duration);
     cm = microsecondsToCentimeters(duration);
    
     Serial.print(inches);
     Serial.print("in, ");
     Serial.print(cm);
     Serial.print("cm");
     Serial.println();
    
     delay(100);
   }
   
   long microsecondsToInches(long microseconds)
   {
     // According to Parallax's datasheet for the PING))), there are
     // 73.746 microseconds per inch (i.e. sound travels at 1130 feet per
     // second).  This gives the distance travelled by the ping, outbound
     // and return, so we divide by 2 to get the distance of the obstacle.
     // See: http://www.parallax.com/dl/docs/prod/acc/28015-PING-v1.3.pdf
     return microseconds / 74 / 2;
   }
   
   long microsecondsToCentimeters(long microseconds)
   {
     // The speed of sound is 340 m/s or 29 microseconds per centimeter.
     // The ping travels out and back, so to find the distance of the
     // object we take half of the distance travelled.
     return microseconds / 29 / 2;
   }
   

Matjaz, sounds like a Slovenian name. Is it?
Anyways this should be relativly easy to do.
Its all about understanding how serial comunication works.
Even if you print("String") it woun't go on the serial port as a string but as a sequence of characters 's', 't', 'r', ect
On the PC side your program must listen to the serial port. Using the function Serial.Avalable() you wait for data to come.
When the data comes start reading it (store it in an array or something similar) and once data is recieved you do something with it.
Problems are when sending multiple data like in your case, you need to know where the first data set ends and the next one starts.
If you send 2 string, like

Serial.print("Str");
Serial.print("ing");

Your processing code can read this as String instead of Str and ing.
This can be solved with a delimiter witch is actualy a sign you don't plan to use in your data but you append it to every data you send.
That way your processing code can read byte by byte and once it reads your delimiter you know this is the end of one message.

Hope i'm making sense. I'm no pro thats for sure.

Thats the way i would do it, actualy will do it when i get the chance (time is the limit).

Thank you dormage!

Yes, Slovenian name :)

I will look up your suggestions, but please by all means, post your suggestion once you have time.

Matjaz