Without using "delay," how can one record the time between say one button push or interrupt and another?
I've tried using an interrupt and the Millis() function a few different ways but I'm stumped. Either I get 0 or Millis() just keeps rolling. I guess what I need to know is can I capture time at point a, then point b, and measure the elapsed time between the two? Because Millis() doesn't start and stop real easy, I'm finding this vexing.