They sound like little hall effect sensors but I can't understand why they wouldn't have some sort of display already. These devices work well with the interrupt facilities on Arduino. You may get a useful start herehttp://www.freetronics.com.au/pages/jaycar-water-flow-gauge"Approx 7" is a bit loose. If you really mean six, you are in luck, as Mega has that many interrupt pins. If you really mean eight, I guess you can piggyback a Pro Mini to get the extra pins. I don't think you need to cycle the display or push any buttons. A single 4x20 LCD will probably do it all.
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16