Flow sensor pulsation.

Regarding a hall effect flow sensor.

Would someone kindly direct me to help achieve the following result.

Which would be the simplest way, if any, by either hardware or software implementation, to turn a flow sensor 5/2.5/0-volt pulsation into a 5-v if rotating or 0-volt if not. Basically, making the flow sensor pin, whichever, on the Arduino a high or low state.

This would be my ideal for the next line of the program.

A pulse-stretcher circuit?

But why do you need to? You can do this in software by looking at the time of the
last change on the pin.

Thank you for your reply. I an totally new to this and have a lot to learn for this project, but I have the time. Where do I learn this?

"You can do this in software by looking at the time of the last change on the pin"

Record the value of millis() every time the value from the pin changes.

Consult this time and compare to a threshold.

Thank you for replies. Situation reviewed and solved.