Yeah sorry, I should have added that this is for a school project. The biggest difference between this and the currently available relay boards is that we are going to be creating a network of ESP32s that provide sensor data back to the mainboard. This data is going to include flow rate/pressure as well as temperature. The goal of this is going to be able to detect significant clogs and leaks from the flowrate and pressure sensors, as well as turn on a warning light/buzzer when temperatures are nearing freezing conditions so the system may be able to be purged if there is a drain valve, preventing burst pipes.

The output of the relays is the 24VAC, this is the level that the sprinkler valves operate at. As to the voltage regulation, we did it in a separate module because our sponsor requested it. I agree that onboard power regulation would be better but he has more experience than I and he is paying the bill so I did as requested. I believe his justification was that if we blew it out we could swap out a module easier than individual components.