I'm using Arduino Uno to operate a latching solenoid irrigation valve by using an H-Bridge to set the polarity of the 12V DC going to the valve. A 500 ms + pulse on a digital output pin turns the valve on and then the polarity is reversed and a 500 ms - pulse turns the valve off.
Now I want to operate multiple valves and rather than using a separate H-bridge for each want to know if I can connect the valves in parallel to the 12V circuit and switch them individually with output from different pins.
It seems this could be done with transistors or a chip. A project I built to switch a non-latching solenoid used a TIP120 Darlington NPN Transistor but that will send current from the emitter to the collector, correct? and I need to be able to have current go in either direction. Is there a way of doing this? Thanks.
Edit to add project description: My current design phase is to irrigate 6 almond trees planted in barrels, with control from soil moisture. The next phase would be to control irrigation, with multiple sensor types, to 270 plots. The "aspirational goal" is to irrigate each tree in an orchard individually so ~ 1,000-10,000 locations so cost and power efficiency are important.