Robin2:
It is not a good idea to use the String (capital S) class on an Arduino as it can cause memory corruption in the small memory on an Arduino. Just use cstrings - char arrays terminated with 0.If you use a cstring you will have to define the size and problem will go away.
...R
The whole project compiles well within the constrains of the Nano...
Sketch uses 12870 bytes (41%) of program storage space. Maximum is 30720 bytes.
Global variables use 1201 bytes (58%) of dynamic memory, leaving 847 bytes for local variables. Maximum is 2048 bytes.
So if I use char strings, they will be one more than than the actual length of the string to account for the terminating null ?
Is there a "SizeOf" function I can use instead of counting string length manually ?