yeah, math would be okay for here, but if it was ever going to be manufactured, which is another of my tasks, to simplify the design and make it a bit more user friendly and cheaper it wont work, which is why i was thinking of something along these lines. But no, i don't know the frequency, yet, ill hook a scope up to it and see, never paid attention to it before, but that is the calibration method currently. What I am really trying to do would be to increase the time between the pulses x8 so that the numbers would out correct.