Convert decimal number to ASCII

I'm thinking about the possibility using the println logger as a way to store Generic ANT data received by the watch for debugging purposes.

However, storing it as a text file is not an efficient use of the 5K storage limit. I'm thinking that I could encode the data as if it were a .FIT record (or a similar binary concept) then write some type of simple decoder to recover the data later when I download the log file.

My first thought on how to do this is to write each byte of data as its ASCII character so I would need someFunction like below to do this.

var num = 65; //num is between 0 and 255
var character = someFunction(num); //someFunction returns the string "A"
Sys.println(character); // prints an A into the log file


Does anyone know of a simple way to do this in MonkeyC?