I have yet to build an Arduino system, but I am very intrigued.
I am trying to build a very simple shower timer, but more as a gag joke rather than for function. I live with two dudes in our late 20's. One guy always takes crazy long showers, we give him crap about it all the time but he won't stop. The last person to wake up has zero hot water. My other roommate and I are very DIY so we want to create a hidden system that will cut the water after, say 5 minutes. But we also want a simple toggle switch to override the system. We plan to install the water shut off valve on the pipes near the water heater.
So, my question, Could I use the following two items to monitor when water flow starts and then cut the water flow after five minutes using an Arduino board? What Arduino board would I need? How about power supplies or anything else?