Relay Shield Question / Sprinkler Valves?

So I have this project where I am using an Arduino to control our in ground Sprinkler Valves.

The specification on the product page says Max 70W DC or 35V AC. Sprinkler valves run 24VAC, so I thought this should be a slam dunk.
(ref: … th=132_134)

The specification on the wiki page, which I seen after I purchased the product says:
The max switching power is 35VDC 70W for each channel. It can be directly controlled by Arduino/Seeeduino through digital IOs with external 9V DC supply.


First question, can this be used to control 24V AC Sprinkler valves?

So I have it all wired up, except for the power supply. The power supply I have says 24VAC 14.4VA. It has two wires, that both have a U on that hooks to a screw. (This was to the old sprinkler control.) In the book for the old control, they are hooked to the screws that say “AC”, and doesn’t say if the one with the white strip should go on one side or the other.

The Seeed Relay board has screws for 9V and GND.

Am I missing something here?

of course that the relay can be used to control your Sprinkler,"The max switching power is 35VDC 70W for each channel " mean that it can support Max 35V/2A AC or 35V/2A DC .

Thanks for replying. Just wanted to be 100% sure before I wired it up. (Didn’t want to fry the board if it was more than it could handle).

That being said, I got it all wired up, the PS light on the Relay Shield comes on, and I hooked up the system.

The issue I ran into: There is no power on any of the COM ports. (Checked with a voltage detector and a meter).

Is there some trick?


you had download the code , contrloled it ? or did you connect the input power of NC(1-4) /NO(1-4) ?