I am confused. How would I use a ESP32 and a relay board? What would I control?I'd use a ESP32 and a 8 channel relay board (or maybe a 16) and wire everything off that. I'd mount that beside the new house fusebox. I'd use momentary "normally open" switches to trigger the ESP based upon a "change of state" of the switch. I'd write the code so the ESP32 Inputs triggered by a ground signal. That way every switch would only need one very small wire to it from the ESP because I'd ground each one to the body locally to supply the ground. I could have used as many switches as I wanted to for every single device. If I would have done that, I could have controlled everything from my phone over a WiFi access point on the ESP and even used timers in the code if I chose to. Temperature sensors and photocells could have been implemented as well. Manual switches could have been grouped together and wired using just one cat 5 wire allowing 8 switches to be wired with just one small cat 5 wire. The sky would have been the limit and the costs would have been far less. There would have been no need for 3 way or 4 way switches and all that 14 gauge wire. Better control, centrally located components, less wiring, less voltage drop and less chance for a malfunction! The boards are only a few bucks and the 32's are inexpensive. Hindsight is 20/20 I guess!
I have the following 12 volt switches:
1. On/off switch at the ceiling at rear doors for the rear LED light.
2. On/off switch high on shower wall for the shower LED light.
3. On/off switch on side of sink cabinet for two LED lights over sink counter.
4. On/off switch on wall above the sink counter for the water pump.
5. On/off switch on bottom of right side overhead cabinet for LED light string under passenger side upper cabinet.
6. On/off switch on bottom of left side overhead cabinet for LED light string under driver side upper cabinet.
Light switches are placed where I will be located when I want that particular light.
I have two shore power 120 volt AC selector switches:
1. A 3 position switch to select shore power or " shore power" from the vehicle powered inverter or off.
2. A 4 position switch to select charging or water heating or air heating or off. In charging position that charges house battery and powers the 120 volt AC duplex outlet string.
No other controls. All 12 volt loads powered by Blue Sea fuse blocks.
One string of 120 volt AC duplex outlets.
All DC and AC wiring done with "SOOW" cords. 14/3 for AC, 12/2 for 12 volt plugs, 14/2 for Maxxair and water pump and 16/2 for LED lights.