dougp:
The first thing to get down is sensing when[color=blue]proxPin[/color]changes . In the IDE refer to: file/examples/digital/state change detection.Next, set the timer up as free-running, that is, it increments continuously. When timer is done, that is, reaches preset, use that condition to shut off the pump.
Finally, reset the timer -
[color=blue]currentMillis = millis()[/color]- when the state of[color=blue]proxPinChanged[/color]goes high.[color=blue]proxPinChanged[/color]will be high for only one pass through the program each time the sensor is triggered.So, as long as pulses are arriving at a certain rate the timer will never time out, keeping the pump on. If pulses cease the pump will shut off after X time.
These are good points. I had not heard of the state change detection before but it looks promising. I will play with it. Thanks for the response