After wiring up each outlet so it can be controlled independently, he set out designing a four port relay board. This was a pretty simple build – four 10 Amp relays and a few terminal blocks.

As the valves use 24V and the motor 12V, standard N-Mosfets and power relays are used for voltage conversion. The remote controller [Gilard] used is actually 20 years old, so the output signal of ...