Hi, I have just started to learn C and C++ and i find it very interesting. I have also pulled my Scalectrix car racing kit out of the basement, and really enjoy racing it. Then I had an idea, that is should be possible to make a program that could calculate the speed of my car (real speed), cound laps and take the lap-time. I have now built a electrical circuit with a 9V batteri that creates a voltage pulse each time the car passes a spesific point. All I need to do now is to make a program that can take this puls and take the time until the next puls appears ... then do all the calculations. I have looked around the web for information, but have'nt found much. Do anyone know how I should do this. Should I use the serial port or the parallell port? What kind of commands do I have to use? What should I be aware of? Could anyone help me? PLEASE.