I'm playing with garden automation trying to make a system capable to autoregulate water pressure using an electrovalve to regulate the water pressure and a water flow sensor ( this one http://www.seeedstudio.com/depot/g114-water-flow-sensor-p-1082.html?cPath=144_151 ) to check output pressure
my idea is to start a water pump and let arduino to control the single electrovalve adjusting opening for every final bistable electrovalve and let the water flow out with the right pressure without hydraulic parts to reduce pressure