I'm messing around with a mechanical ball valve and my arduino. The valve works by applying 12v to a red wire to open or to a green wire to close (with a black wire always connected to ground.
Now ... I can happily make this work with two arduino pins, two transistors/mosfets and all the gubbins, but I was wondering if there's a more efficient method, which relies on just one pin ... Perhaps that the 12v would flow to the green wire by default unless the transistor was activated, which would redirect the flow to the red wire?
Not really a dealbreaker, I have enough free pins to use two, but it's bugging me!