Dear all,
with this post, I would like to introduce myself and my project. I am an 38 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 are:
- Undoability: The system should be exchangeable with a classical electrical installation without removing any wire from walls
- high WAF: Although the WAF is a highly sexist, its principle is to be used - 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, now hosting the above mentioned hardware.
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 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 openhab
- an RGB lamp (included in the wall terminals)
- all wall outlets can be rewired to be switchable
- all blinds are controlled by openhab
- 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,âŠ)
- 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.
So, where am I?
We are living in this house while working in it, which is a special kind of fun.
Nevertheless, we already have finished wiring the second floor and soon we will be able to move up. When it comes to home automation, the whole server and infrastructure is already up and running, server, rack, network cabling for the new floor âŠ
We have three clients wired and working in the first floor, which is already pretty cool to use
Still they are not completely wired, since I need to wait for the wallpapers to be attached to wire all the switches, sensors and wall outlets. So I only have a small amount installed for testing.
I also have a MII-light test system and Sonos speakers that are integrated. The system already knows when our mobile phones come home (i.e. set up an WLan connection) and monitors sensors. It controls 90W of LED lights in ten different circuits and actuates the blinds. It also controls the info lamps in the connected rooms.
So the basic functions are all set up and ready to be scaled to a higher level.
Whatâs to come?
Basic functions:
- scale the above mentioned functionality up for the whole house
- several easy rules like: âturn infolamp purple when room humidity is too highâ âafter 20:00h do not actuate the door bell but blink the info lightâ
Example advanced functions/tasks:
- open and shut window blinds depending on the sun position (easy) and the desired room temp and the outside temperature (summer sun heats up room: unwanted -> close blinds; winter: sun heats up room: wanted: leave blinds open)
- make the data of heat pumps, water meters and energy meters available and correlate them to anything.
The hard stuff:
- Forecast the amount of solar power over the day by interpreting the day of the year and the weather forecast. Correlate a list of jobs (washing machine, warm water heat pump, dish washer, âŠ) into the forecast to use as much solar power for these tasks as possive
- maintain the whole system easily
So much for my brief introduction, there is a truckload of more details, just ask if you are interested.
Last but not least: I would like to say thank you to the openhab developers and the community making all this possible. GREAT WORK!
Cheers,
Christian