Dear all,
with this post, I would like to introduce myself and my project. I am an 42 year old engineer interested in mostly any technical stuff you can find (disclaimer: interested does not necessarily mean being successful with it 
).
When my family and I decided to buy a house that needs to be complete rebuild (âKernsanierungâ for you German speaking readers), I was keen to install a home automation that supports us in our daily life, without complicating it.
(sneak preview: it worked ;-))
So my main key goals were:
- Undoability: The system should be exchangeable with a classical electrical installation without removing any wire from walls
- A non technical person should be able to use and, to a certain extend, repair the system without f.ex. using a linux console
- Green footprint: making the house as energy saving as possible
- Fun: Going through the process of setting up a system and maintaining it should always include the fun of building and using something self-build
- Money: I did not want to spent too much money on sensors/actuators/home automation components
My Approach of doing this:
Cables:
To be able to undo the whole automation and rewire everything to a classical setup, it is necessary to wire everything that might become 230V in the right cable type for 230V. In addition to this, these wires must be guided to a electrical distribution rack. This can be done as one rack for the whole house (tons of cables and a HUGE rack) or as one rack per one or two rooms.
I went for the second one, this saves cables and complexity and supports my slave hardware.
Infrastructure:
Since I already running an home server and the house should have gigabit network wall outlets âeverywhereâ I did need a decent switch. Since I wanted to have a second small server (Cubietruck) to host openhab, I needed a second computer case and well, a second switch (separating home automation traffic from normal network traffic) Ebay Kleinanzeigen then found me a nice server rack for my basement. Some two years ago I needed more power and upgraded the cubietruck to a full blown server. I also changed from OpenHAB to Homeassistant for various reasons.
All lighting and all clients shall be powered with 24V DC, therefore I have a central 24V 240W power supply that is distributed to each electrical rack.
Home automation hardware:
Since I now have electrical distribution racks for each two rooms, I need clients in these racks to control the rooms themselves. Any hardware on the market was way too expensive or too featureless for my demands, which are:
Basis in every room:
- sensors for temperature, humidity, brightness (installed in the wall terminals)
- all switches connected to HA
- an RGB lamp (included in the wall terminals)
- all wall outlets can be rewired to be switchable
- all blinds are controlled by HA
- all windows are checked for being open
Optional features:
- switching other loads (f.ex. LED stripes, washing machines)
- supporting motion detectors
So buying was not an option: Letâs build it 
!
The final âroom clientâ hardware has the following features:
- 13 PWM controlled OUTs, each controlling either an Meanwell adjustable current source (powering high power LED lamps) or switching 24V loads (stripes, relais,âŚ)
- 23 digital INs, (every voltage from 5 to 24V DC will be accepted as âhighâ)
- barometric pressure sensor
- current and voltage sensors for the total client energy consumption
- 4 sensor inputs, supporting the above mentioned sensors and the RGB lamp
- 4 outputs directly controlling relays
- Communication via Ethernet and the MQTT protocol
- USB connection for programming it and getting debug information
Hardware wise, I am using an Arduino Mega with an Ethernet shield as a basis. Attached to these is my âroom clientâ shield that itself is connected to two extension boards making the IO available. Every IO is somehow protected against 230V, be it through powering a relay, the protection system of the meanwell supplies or optocouplers.
All this is happily working with HA, but well thatâs just the basis.
Which integrations am I using?
Sonos
Ebay marketplace was kind enough to supply me with a stream of used Sonos speakers now population our house. Never underestimate the fun of grouping all speakers and listening to your favourite tunes in full blast
Heating System
This one was a real challange. I have a highly efficient heat pump system nicely giving Ebus signals. Still getting the signals into HA understandable terms was quite difficult. I ended up with EBUS to MQTT to NodeRed to HA. But it works. Since the system is pretty much self optimizing, I did not bother building controls for the heating in HA. But I get a lot of interesting data about the various states.
Cooling chamber
This one is less of a HA topic but more of a cool project. Remember the heineken ad where the guys open a walk in fridge? Weeeeeellll, I have a heat pump for my warm water supply which creates warm water and cold air. You could just guide the cold air outside or, you build a insulated room next to your kitchen where you put the cold air before sending it outside. Thereâs you no-cost walk in fridge! (Of course, it has temp and humidity sensors for HA)
Door Bell
Well likely nothing to brag, still the switch is connected to a room client. Therefore I get notifications via telegram and lateron, when I have finished the nice doorbell case, I will also get a picture of whoever is on the door.
Mailbox
Since the outside of the house was also insulated, I was able to put a lot of cables there. One is directly entering the mailbox from the inside. I could the take some ESP, LEDs and switches. Now we get a telegram notification whenever someone puts mail in. Additionally the mailbox itself had some plexiglas in it, which is now backlit whenever there is mail.
Plant irrigantion system
I have build a system with a water bassin, pump, soil humidity sensor and a ultrasonic sensor. The automation should be straightforward: If dry then water, if empty send message: I need refilling.
Solar system with battery
I have a small solar system (300Wp, two modules) with MPPT chargers that charge a 18650 battery (10s19p) made from recycled notebook batteries. This is used to power my 3d printer. HA gets all the data:
- incoming voltage/current/watts
- detailed battery data, all voltages, all currrents all states
Tradfri
Well, I have Ikea lights, too.
TV
When I look at my TV system sometime in the 90âs, there was a truckload of devices and cables involved. For the living room, I did not want this any more. Therefore I made the TV go up/down so it is hidden when not used. With the Sonos playbar and some rear speakers we do have the surround system in place. All other things like the kids gaming system are hidden aswell, so that nothing technical is visible.
Of course we have RGBWW indirect lighting and a switch for scenes 
ESPHome
Oh my god, what a incredible project!
ESPâs keep popping up in my house. I cannot stress enough what an incredible acceleration ESPHome is for every project I am doing around here. Short example? My older son wanted to do a small project with me, so we did look around the shop whatâs there. We decided on a Mobile reading light. So taking a charging board, some 18650âs DC/DC converters and some WS2812 Stripe and and ESP, we did a Fusion360 model, printed the parts and programmed, well configured the ESP. and boom: we have a mobile reading lamp that is stand alone but also controllable with HA.
Testsystem
I made a HAL9000 inspired device that gives me some sensors, llights and buttons to test automations and ideas. See here:
https://community.home-assistant.io/t/hal9000-having-a-test-sensor-and-switch-system-for-playing-with-homeassistant/220332/7
So much for my brief introduction, there is a truckload of more details, just ask if you are interested.
last but not least: Thanks for all the great work everyone is putting into Home Assistant and the attached projects. This is awesome!
Cheers,
Christian
PS.: to be fully honest, I copied some of the content from my post in the OpenHAB Forum, but I asked myself for permission, so I guess its all right!
