While working as a volunteer on the Kibbutz SDE-BOQUER, near Beer-Sheva in Israel, I was impressed by the degree of automation of the irrigation infrastructure, which was computer-controlled, but via a micro-hydraulic actuator system, which I didn't understand. The University of the Negev is almost next door, and I'm sure someone there could give you an idea of what might be both available and practical.<br>
Cheers.