The attenuator was inserted between a wireless receiver and a microphone amplifier. Using the 20db pad for running a bass head's line out into a mic input on the mixer.

Kit comes with everything you need except a battery compartment or power supply which you’ll need to power the water pumps. The wiring diagram has a small issue. Other than that, simple design and code is flawless.

If you have access to a nano, it has 8 analog read pins so you could support up to 8 plants. The only thing i'll add is a water level float switch in the reservoir to tell me when the water supply level is too low to run the pumps.