Loxone: the formula to a real smart home

October 29, 2018 Jeff Rhys-Jones No comments exist

So what exactly is a ‘Smart Home’?

Is it a house that has a doorbell camera that can record potential intruders?


Or is it as house that has a big ‘Beware of the dog’ sign on the front gate, when the home owner doesn’t have a dog?


The answer, is of course, these are both ‘smart’ things to do, they both might put off intruders, and yes, the latter is undoubtedly the cheapest and easiest to deploy! They are however both technically static standalone ‘security features’.


Just because something is smart to do, it doesn’t mean that it is ‘smart’ by nature. Static features are not able to automatically and dynamically react to changing situations.


The term ‘Smart Home’ is being so increasingly used and abused I am even loathed to using it myself. But that’s a shame. In a bid to try to wrestle the definition back from serial misuse, I thought I would have a go at making my own distinction.

Real smart does real feel

At the heart of a real smart home is not necessarily just a skip load of widgets, functions and features, but interoperability and automation. The power of automation is completely dependent how features, functions and data can interact together in such a way that they can then change how systems work in real time. Dig right down into what makes automation possible, and you will find that everything is basically running on… logic and maths.


So the ability to be able to ‘program’ with the building blocks of logic and maths is a crucial feature of a real smart home system.


I am not a mathematician, I am just someone that understands a little bit about logic. I only just scraped a C at GCSE maths. However, despite this, I recently embarked on a mini project in which I used a little maths, some logic, and my Loxone miniserver to take data from two essentially ‘dumb’ devices and used this to create ‘smart data’ out for my home. My old Maths teacher Mr Baxter would be proud, though I never did forgive him for writing in my school report that..


Sometimes I wonder if Jones is still breathing..


So anyway the project….


Having turned distinctly chilly & windy as of late, I was looking at where the data from the house anemometer (wind meter) and outside temperature gauge displays on the house control iPad, and it struck me that I didn’t have any display data for ‘real feel’ or ‘wind chill’ temperature. I have temperature. I have wind speed. Surely then ‘wind chill’ (some combination of the two) would be simple to work out? Hmm!

A ‘Quite Interesting’ little formula!

After a little Googling I became a tad despondent. There are many online wind chill calculators out there, but I wanted to use my Loxone Miniserver to make my own calculations, with my own weather station data. For that I needed a formula. When I got it, I next thing I needed to figure out, was what on earth to do with it!


It turns out, the formula for Wind Chill (Celcius & KM/h) is this:

(Where T is the air temperature in degrees Celsius, and V is the wind speed in kilometres per hour)


My first thought was that this formula looked like something out of QI. With confidence in my own abilities, and personal experience that with Loxone it’s generally a case of not ‘if’ something is possible, but ‘how’, I got stuck in.

Maths warm up: M/S to KM/H

The first little problem is that this formula required ‘v’ in KM/H, however my weather station is giving me wind speeds in meters per second.


The first (easy) part is simply to use a couple of Loxone maths block to convert the wind speed coming off the weather station from m/s to km/h. Very straight forward case of multiplication and division.

(Above: super simplistic meters per second to kilometres per hour converter)

Where there’s a will there’s a chill!

Maths not being my best subject the next bit (main formula) was somewhat of a challenge for me. I stuck to my trusted problem-solving methodology, which is to break a problem (in this case, a formula) down into smaller parts and deal with it that way.


I basically tackled the equation in sections, multiplying the contents of the brackets, feeding in my temperature and wind speed adjusted to km/h. Then the very handy formula block enabled me to work out the wind speed to the power of 0.16 part.


Running the configuration in simulation mode (using static constant hard coded values for wind speed and temperatures) I could see that program worked, because I was able to compare the programs output with online wind chill calculators. However, after hooking it up to my live temperature and wind sensor data, out came some totally crazy temperatures.


I soon discovered, much to my dismay, that for this formula at least, wind chill cannot be calculated for wind speeds of 1.2 m/s or less. My dinky wind chill program would therefore splurt out completely spurious figures whenever there was little not no wind. Not good!


State block to the rescue here, and I was able to bolt on a little extra routine that essentially overrode the wind chill temperature value when the wind speed dropped to 1.2m/s or less. Under this condition, the text ‘NO WIND’ is sent to the readout instead of the spurious ‘feels like’ value. Victory is mine!


(Above: the wind chill formula transposed to a Loxone program with output suppression for no wind)

Wrap up!

In the grand scheme of things, yes this was a relatively simple formula based program to create, yes it’s not particularly ‘sexy’ and it just scratches the surface of the sort of complex programs and routines you can create with the Loxone system.


But it struck me that it’s really a rather perfect demonstration of impressive programmability that the Loxone system has its core, and the visual programming system (Loxone Config) which enables ‘visual thinkers’ like me to actually build and ‘see’ the program working (and almost as important, not working!).


The point of this post? It’s not about any formula in particular, but rather the fact that you can put formulas into Loxone it in the first place. This, in my view, is the acid test a real Smart Home.


So if you happen to be looking at a Smart Home solution, just ask yourself, does it pass the magic Smart Home formula test, which is: Can it actually run a formula?!?


If the answer is no, then I suspect the solution you end up with might be a bit smart


It just won’t be real smart.


(Above: final read out on the Loxone app, with ‘no wind’ and ‘feels like values)

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