lets say your variable is called X .

then try something like this.
bind x to mouseX so whenever you move the mouse ( change the variable) it gets printed.
simply create another temp variable and make it x but after the check.
so if x changed x is not tmpX at the beginning of the next loop and the value gets printed...

1. int x ;
   
   int tmpX;
   
   void setup() {
     size(600,400);
   
   }
   
   void draw() {
   x = mouseX;
   if(tmpX!=x)println(x);
   
   tmpX = x;
   
   }
   
   

perfect! thanks a lot.