Does anyone know please?

Apparently, the problem isn't with the code above, but with your reader, no?

Hi,

I wasn't implying the reader was broken, but that if it doesn't read continuously the tag, I don't see how Processing can force it to do it.

Hi,

" I want the reader to keep reading the tag"
I supposed it was your main problem...

First, you don't need to check other values if one is found, so 'else' should be used.
Checking a boolean against true or false is quite redundant, too.
And your comments are not only redundant, but invalid past the first test...
So part of your code can be written as:

1.   if (RFID1.equals(inString)){  //checks inString to see if it matches the first RFID
2.    println("Card 1");
3.    jpg = loadImage("card1.jpg");
4.   }
5.   else if (RFID2.equals(inString)){
6.    println("Card 2");
7.    jpg = loadImage("card2.jpg");
8.   }
9.   else if (RFID3.equals(inString)){
10.    println("Card 3");
11.    jpg = loadImage("card3.jpg");
12.   }

And then, you can add:

1.   else {
2.    println("No Card");
3.    jpg = loadImage("default_card.jpg");
4.   }

But perhaps serialEvent() isn't called in the last case.
In that case, we have to adopt a different strategy, like reverting to default image if no serialEvent came after a while.

Hi PhilLo,

Something like this:

1. // Global
2. int lastEventTime;
3.  
4. void serialEvent(Serial myPort)
5. {
6.   lastEventTime = millis();
7.   // [...] Other stuff
8. }
9.  
10. void draw()
11. {
12.   if (lastEventTime > 0 && millis() - lastEventTime > 500) // Half a second
13.   {
14.     jpg = loadImage("default_card.jpg");
15.     lastEventTime = -1; // No need to reload the image several times
16.   }
17.   // [...] Other stuff
18. }

may I ask which rfid reader you are using?

Hi,

It is not real code, it is a blueprint, you have to understand it and to copy relevant parts of it in your own code above.