Originally Posted by
howardcano
The PC must determine the loop crossing time for each transponder by averaging the timestamps of the first and last ID messages for a given transponder within a certain time window (for instance, after no messages have been received from the transponder for, let's say, 0.1 second).
Then the PC must then calculate the lap time for each transponder by subtracting the previous crossing time from the latest crossing time.
I think the decoder should determine the loop crossing it is not to hard to do and gives the pc more time to run other task.
to determin the crossing time my IR decoder counts the passing HIT's (up to 255 max) then uses the center 2 hits and adds thenthen devide by 2 giving center of the loop. It is not perfect but it is within .01 sec.
having more then 5 cars pass within one half second under the loop causes problems (lost hits)
on average my 20mph real speed test shows 30 to 40 hits per car
at mod speeds fo 43mph I get 15 to 20 hits
if 5 cars go under the loop at the same time then expect only 4 to 7 hits per car at 43mph.
if a car sits under the loop then it counts up to 255 hits and waits for the car to exit the loop for a minimum of 1sec before starting a new hit count. otherwise all you have to do is sit under the loop to win the race
