Need Advice on Watering System

Just built three new elevated 3'x8' planters and want to install an automated watering system because I've done a sh!t-poor job of manual watering over the years. Can y'all give me some direction on the best type of system and a good starting point for the settings, i.e., how much water and how often. California hardiness zone 9b I believe - summer highs above 100 10-15 days a year. My garden gets a tremendous amount of direct sun, so much so that I'm considering putting shade cloth on the south-facing side of my planters. Thank you!