PeterH you are right I want to look down at the display and have it tell me if I am ahead or behind of a previous ride. If i record my speed or time from each wheel rotation, in general i should have a good indication of where i am at. I have a bike computer that logs my rides now, but there is nothing that gives me a real time update that reads off a wheel sensor.
Waiting for my SD shield now, just was hoping someone knew how to compare the data in real time.