Serial port with Processing

[dragonuv]

I have uploaded this sketch into the arduino:

Code: [Select]


void setup() {
   pinMode(2, INPUT);
 Serial.begin(9600);  
}
void loop()
{  
   Serial.println(analogRead(2));
}


and the analog pin is connected to the arduino's 5v, which means in the serial port it has to show only numbers around 1023.

though i have tried to read serial data from processing, it gives me numbers lower than 60. here is the processing code:

Code: [Select]

import processing.serial.*;
Serial myPort;  
int val;    
void setup()
{
 String portName = Serial.list()[1]; //com3, same as arduino
 myPort = new Serial(this, portName, 9600);
}

void draw()
{
 if ( myPort.available() > 0)  // If data is available,
 {  
   val = myPort.read();         // read it and store it in val
   println(val);
 }
}

what can cause this problem?

[Grumpy_Mike]

what can cause this problem?

When you write from the arduino you are sending several ASCII bytes. When you read from processing you are only reading one byte.

See:- http://www.arduino.cc/playground/Interfacing/Processing

[dragonuv]

I'm having a problem with this line:
import cc.arduino.*;
the code says "The package "cc" does not exist. You might be missing a library"

although I have downloaded the library for firmata v1 into the processing libraries folder

[dragonuv]

anyone knows what is the problem now ?

[zdroshnya]

You must have the hierarchy:
<Processing sketchbook>/libraries/<library name>/library/<library name>.jar

best

[dragonuv]

thanks very much, that helped.

[Aniss]

Don't know if you solved your original problem, but as Grumpy said it's because you're sending 2 bytes at a time when you send an int value...

Here is a method of sending and receiving int values that works for me:

Arduino:

Code: [Select]

Serial.print(0xff, BYTE); // Sync byte
Serial.print((val >> 8) & 0xff, BYTE);
Serial.print(val & 0xff, BYTE);

Processing:

Code: [Select]

while (port.available() >= 3) {
   if (port.read() == 0xff)
     val = (port.read() << 8) | (port.read());
}

[HM]

zdroshnya, thank you very much, this is the hint I needed.
The problem of the normal arduino installation is the name of the file.
It is written "Arduino.jar" and so, I've got every time this error message.
I have renamed the file in "arduino.jar" and the library works well.
The guys of the arduino project should corred this in the "processing-arduino-0017.zip" file.

thanks a lot

Helmut