What he said, double! I have a half dozen microprocessor and relay boards on my desk that all take different code. Everything from simple ASCII characters sent out a serial port to an RS-485 DMX control interface. Although the fundamental concepts are the same in all of them, the "devil is in the details" is absolutely the truth. Each implmentation is unique.
I also couldn't agree more that the Arduino is a great place to get started. There's a VERY active developer community, lots of good tutorials and examples and plenty of people around to help you if you get lost.
Spend a little cash, get yourself a little arduino test setup and start coding! Give a yell for help.
This is a project I would like to tackle in the near future in my e39. subscribed.
offtopic. notec- which skin are you using for your centrafuse? I like how clean it is!
I'm using a Centrafuse skin I made, called Noir. Thanks!