Arduino for Unity Output

Hello there!

I often find how an arduino could be used as input to control unity via serial communication. This mostly sends a character over Serialport which will be handled by the arduino sketch (for instance like in this example: http://r3dstar.co.uk/?p=211) Is it somehow possible to pass the arduino some integer values which are calculated in unity instead of characters in the case I want to control an actuator? Maybe someone got an idea for me. Note that I unfortunately can´t use the Uniduino plugin (which is pretty awesome actually) because I need to use some external arduino libraries. Thanks in advance!