i have found whiles attempting a simular project. that the were a few ROBOTIC sites out there which sell controllers which connect to the parralell port STEPPER MOTOR CONTROLLER.... I had been looking for ways to control an animatronics head.. the commands needed to controll the output to the port was my problem. you would have to create or BUY a module.... very expensive...
the CENTRONICS interface has a data bus and you would need a binery (digital to analog conversion) to take place... the circuit which i designed needed a binary input to control the external devices... 10101011, my problem was that i needed to know how to output binery to the rs232 serial or paralell port my soultion was that to output a binery number to the paralel port this would be done via the PRINT COMMAND.. whenb controlling a printer device the characters are sent to the printer in a binary form ASCI codes etc....
so to control a wave i may need the output to be 101010111 101011101 etc so i would print the cha ggggggaaaaabbbbb which would correspond to a movement on the stepper motor...
woah : ive gone a bit far, but they do have controllers alreadyt built.
Girder, homeseer, these programs only control X10 devices...
but if you have a stepper motor controller you can control home ROBOTICS or ROBOTIC ARM, etc.
A SPECIALIZED PIC controller chip is needed BUT easily bought for small money and programmed at home for your own custome use...
but ready made PIC's as i say are available SEARCH (stepper motor controller) they often come with etensive source code & activeX controls for use within .net or visual studio