stepper motor control visual basic parallel port
Get an IO dll that allows you to output on the parallel port on Win2K of XP. Then use the Win32 API calls QueryPerformanceCounter and QueryPerformanceFrequency to get the timing resolution you need (I don't think the millisecond functions give enough resolution). I used an array (better to use a linked list but it was a quick and dirty piece of programming for a student friend) to contain some StepperControl structures (or types in VB) that contained stuff like microseconds between step, steps per revolution, stepper direction, current step, etc, used to control each stepper. Then you have a tight loop where you check to see if the time interval for each stepper has been reached, if so step it. It was a pretty cool project, we controlled two stepper with the MS Speech Recognition software to have the two motors running like a winch and a winch base. The kid and his partner both spoke poor English (they were from Hong Kong) and the speech recognition software didn't miss one command. They got A's for 'their' project and I got a free dinner.