When you’re trying to turn on and off water flow that is not under pressure, the best solution is what is called a gravity feed solenoid valve. A “regular” solenoid valve is a “pilot valve.” That means it uses the pressure of the liquid to pilot the operation of the valve. A small amount of the flow is diverted when the solenoid actuates and that flow is used to open the main body of the valve. In a gravity fed system there is usually not enough water pressure to use this method, so that is why gravity feed valves are used. Their actuators have enough strength to open and close against the flow.
As you may already realize, the Arduino will not be able to supply the power to control a solenoid valve on its own. However, we have created an integrated solenoid valve and power control system so your Arduino can directly switch the solenoid valve on and off. Now there is no need to mix and match components from various manufacturers and wire together relays or power drivers, suppression diodes or connectors. We’ve put it all together in a straightforward, low-cost package that’s Ready to Run.
Here is a sample Arduino sketch that will turn the valve on for 10 seconds when a pushbutton is activated.