Hi. To communicate between Rpi and Arduino use Mysensors sketches. They work perfect (more - they work in Arduino, so even without LAN you will be able to use all automations). If you connect Arduino with Rpi via USB and use Mysensors - Home Assistant will create .json file and store all states there. Unfortunately I have very limited time so I cannot help you wiith the code till july 
Hi, do you have current diagram of your installation?
Hi. Please check out my Album I will try to send something new each week because I am currently working with final wirings 
https://photos.app.goo.gl/qZVyD4EscBhZx3mp6
Woah 
Well, hopefully this will all work out they way you planned it. It certainly looks… impressive 
If there is only one advice to give, run some “normal” 230V wiring to all of your switches, outlets, light fixtures and all the other places. Even if you don’t use it. Just so it’s there and allows your entire electrical installation to be back-converted into a “normal” dumb one if needed. At the very least run some conduit with pull wires while your drywalls are still accessible.
If you don’t do that now, the day you (or maybe your children) will want to sell your house will turn into an insanely expensive nightmare. Think about an exit strategy. Someday all what you do now will inevitably be obsolete and someone (maybe yourself) will want to replace all of it with something completely different.
Hi. Thanks for advice - this is exactly what I did. Everything is a standard 230V installation, even wall plugs are standard. The main difference is that I use SSR relays (and normal relays for blinds) at the end, which are wired with Arduinos. Maybe it looks complicated, but in general the idea is easy. It is only hard to wire everything (there is in total 2,6km UTP cal 5e cable) and create good quality code. If someone wants to change to normal installation - he will change it easily - he just need to throw out relays and wire switches normally with 230V. Everything is well commented in code + I have prepared instruction + I have also a “backup” arduinos, rpis. I will try to put everything inside this album, but this year I have a lot of things to do and I work with wiring at night only…I thought about this idea for 2 months until I started so I’ve thought about all pros and cons.
Hello,
I would like to connect more arduinos to RPi, HA i followed instruction @Michal_Nowakowski provided here but it doesnot work,
I have it coppied here
but I’m getting a integartion error message:
Integration error: arduino2 - Integration 'arduino2' not found.
if I change it to arduino2 and arduino3 in configuration I’m getting same integartion error for arduino2, arduino3
anything I have missing here please?
Hi. I think that “Arduino” plugin could be changed. In the integration webpage Arduino - Home Assistant it looks like this is deprecated. I suggest to go for Firmata integration, or use Mysensors sketch and connect each Arduino to any USB hub (or separately per each USB on your Rpi or other hardware). You should be able to see and use each Arduino separately. I am using 6x Arduino with Mysensors and works well for 3 years now 
It is not a plugin it is an integration. If you want to change the page to point people to the mysensors integration, use the edit or feedback button.
Hello @Michal_Nowakowski , I’m interested in mysensor solution, I followed instructions MySensors - Home Assistant but I’m completly lost,
I have
- installed inttegration
- uploaded example sketch,
- configured integration in config file
logger:
default: info
logs:
mysensors: debug
homeassistant.components.mysensors: debug
mysensors:
gateways:
- device: '/dev/ttyAMA0'
persistence_file: '/home/homeassistant/.homeassistant/mysensors.json'
optimistic: true
persistence: true
retain: true
version: '2.0'
but I’m not able to find any button or relay in HA to implement them into dashboard.
is there something more to setup? in main /config/configuration.yaml file? or somewhere else?
could you please give me excample what else should be set.
thank you