I am writing a custom software to communicate with a obd2 enabled ECM for an instrumented vehicle for a driving study. So i have been reading up some obd2 stuff and i thought it had some "interesting" way of doing "real time" variable display.
http://en.wikipedia.org/wiki/OBD-II_PIDs
And here's an example of communication from ELM320 datasheet (which i am using to convert obd2 to rs232) http://www.scantool.net/download/ELM320DS.pdf