Computer controlled devices?

So I totally got the best idea ever: I'm gonna make a serial/parallel port controller for devices, and maybe later on get to the system operate robotic stuff. So I've been digging up some plans and I'm starting with C/++ or PHP. And by sending decimal values from 0 to 255 I could theoretically power up some controllers, like transistors. The way to this is  by sending decimal value, it gets converted into binary and  if i send 255, all pins are on, and if I send 0, no pins are doing stuff, and so on. Now by using timers to be triggered by this, I can be farely accurate of how long a motor will run and this will enable me to calibrate, and check positions of motors or other components. What I should do, I don't know, what will I do? Well lets say it will be awesome! :D

-N