I'm using a DS300 lap counter for detection of laps, and using the parallel port for power control. When my timed race ends, there is a difference of about 8 seconds between when the DS300 times out and when PC Lap Counter times out, so the cars continue to race for that 8 seconds, and if a car passes under the DS Light Bridge, its lap doesn't count.
My computer is running Windows XP. Can you think of a reason why there is this much of a difference in timing between the DS and PCLC? I thought it might be because PCLC has a countdown before the start of the race, and the DS300 starts immediately; would that explain the difference? And if so, how do I avoid the discrepancy? Do I omit the start light countdown?