Hello cgdsdkc
One place to start looking is this part of your code, and what values k takes on as the program runs.
pos1Array[k]=pos1;
pos2Array[k]=pos2;
sensorArray[k]=sensorVal;
k=k+1;
In particular, each time you go round the main loop(), what value do you want k to start at? Where in your program are you setting it to this value? How do you make sure that k will not get bigger than the size of the arrays?
Regards
Ray