I wanted to know How to control an external device with the help of a computer. Suppose i make an electrical device which contains of 5 switches and a combination of those can make my device do several things. How is it that i can control it through a computer. Moreover even if I am able to put the switches on or off with the Help of a computer is there any way by which i can write a program to define various actions performed by my machine and make it work by running the program. Guys! anyone who can help me with that would help me create something you people would like getting ur hands on.