Home Assistant? What Is This Thing?

In the previous article, I had ended up with my HomeWizard P1 Meter, a smart plug and what still seemed like a reasonably simple idea: retrieve their data and start playing around with it.

My research led me to Home Assistant almost immediately.

Home Assistant?

The name does give you a clue. And if you type “open-source home automation” into Google or start watching a few videos on the subject, it probably won't take long before Home Assistant shows up somewhere.

Before installing anything, I decide to take a look at what I'm getting myself into.

A few searches and a few videos later, I quickly understand two things: the ecosystem is huge, and the number of devices and services that seem to be integrable is pretty impressive.

That little drawer I had opened in the previous article?

It was much deeper than expected.

Looking back, I obviously know today that other solutions exist, such as Jeedom. But at the time, I don't really look any further.

So I'm not going to tell you that Home Assistant is better than everything else. I have no idea: I simply haven't experimented enough with the alternatives to make that comparison.

Home Assistant is the one I stumbled across. It seems capable of doing what I'm looking for and, more importantly, in my case, trying it costs practically nothing.

So why not see where it leads?

Fortunately.

The ecosystem is vast enough that trying to study everything before installing Home Assistant is probably an excellent way to make sure you never actually install it.

Looking back, starting small seems like a pretty good approach.

One integration. A few devices.

And see where it leads.

In my case, it's going to lead quite far.

But I don't know that yet.

Right... let's install it

I already have infrastructure at home capable of hosting virtual machines. So my entry cost is exactly zero euros.

I choose to install Home Assistant OS in a VM. In my environment, it seems like both the simplest and most flexible option.

I'm not going to go through every installation step here. The official documentation does that very well and, frankly, the whole process is simple and quick enough that there's no point turning this article into a tutorial.

A few minutes later, Home Assistant is running.

All that's left is to integrate HomeWizard.

Two clicks later...

I search for HomeWizard, launch the integration and, a few clicks later, my P1 Meter and smart plug are there with their data.

Oh.

That was easy.

But Home Assistant doesn't really stop there.

As soon as it is installed, it also discovers a whole series of devices already present in the house. Some are obvious. With others, I hadn't even considered that they might have anything to tell Home Assistant. There are even a few I had practically forgotten about.

And several of them can also be integrated in just a few clicks.

I click, I add them, and I see what appears.

I'm a little lost.

I start looking around the house with a slightly different eye.

The television? The alarm? The Google Nest devices? The phones? The cars?

The same question keeps coming back:

“And this? Can Home Assistant do anything with this?”

And quite often, the answer seems to be yes.

Sometimes directly, sometimes through an additional integration, sometimes with certain limitations. And when an official integration doesn't exist, a community-developed project can sometimes take things further anyway.

To be perfectly honest, I even integrate some devices without having the slightest idea what I'll be able to do with them.

Home Assistant tells me it has discovered something, I see that an integration exists, I add it... and only then do I look at what has appeared.

Information? Controls? States I didn't even know existed?

No idea.

We'll see.

Some integrations are immediately useful. With others, for now, I simply confirm that they work and move on to something else.

I started using Home Assistant because I was looking for a solution to one very specific problem.

And now, I'm adding things before I even know what problems they might solve.

A house seen as a black box

Let's get back to the reason I ended up here in the first place: energy.

With HomeWizard integrated into Home Assistant, I finally have the information from my electricity meter. I can see what the house draws from the grid and what it feeds back into it.

Great.

Except that, looking at those figures, a new limitation quickly becomes obvious: the meter sits at the boundary between my house and the electricity grid. It sees what comes in and what goes out, but it can't tell me what's happening behind it.

In the end, my house is still a black box.

Let's say that at a particular moment the meter tells me I'm exporting 1 kW to the grid.

Are my solar panels producing 1.2 kW while the house consumes 200 W? Or are they producing 3 kW while the house is simultaneously consuming 2 kW?

From the meter's point of view, the result is identical: 1 kW goes back to the grid.

For me, however, those are two completely different situations.

Since I have solar panels, the next step becomes fairly obvious: I should integrate their production into Home Assistant as well.

Another thing to integrate.

What about the solar panels?

I start looking for a way to retrieve information from my photovoltaic installation.

In my case, what I need isn't directly available through a native integration, but a third-party integration exists that can retrieve the data through the API of the system used to monitor production.

A bit of research and configuration later, my solar panels appear in Home Assistant too.

That means depending on an external service.

Is that ideal? Probably not.

Is it really a problem at this stage? Not particularly.

I'm still experimenting, and I already have enough things to discover without turning every single one of them into an engineering project aimed at eliminating every possible external dependency.

More importantly, if that API disappears tomorrow, my solar panels will continue producing perfectly well. I'll lose information in Home Assistant, not the function itself.

At this stage, I'm fine with that.

The solution exists, it works and it lets me move forward.

For now, that's more than enough.

But something is starting to become particularly interesting.

My electricity meter has its data. My photovoltaic installation has its own. My HomeWizard plug has its data. Other devices around the house probably have theirs too.

Home Assistant is starting to provide a place where all that information can finally come together.

And the house is slowly starting to look a little less like a black box.

Seeing consumption is good. Understanding it is better.

I can now see what the house consumes, what the solar panels produce and what gets exported to the grid.

But I still don't really know what lies behind the house's overall consumption.

How much does my IT infrastructure consume? What does the office account for over the course of a day? Are some devices unnecessarily left running for hours? And, more importantly, would I be able to detect a device whose consumption suddenly started deviating from its usual behaviour?

I'm not particularly interested in tracking every last watt just to save three cents. What is starting to interest me more are the trends.

Understanding what normal consumption looks like. Identifying a few possible optimisations. Being able to notice something unusual and, perhaps one day, receive an alert when a device isn't behaving as expected.

For that, I would obviously need more precise measurements than the overall consumption of the house.

And that's when I think back to that HomeWizard plug.

It measures the consumption of whatever is plugged into it.

At a reasonable price, a few additional smart plugs could therefore let me measure specific loads without touching the electrical installation: the IT infrastructure, the office, or simply a few devices whose actual consumption I'm curious about.

Right.

Another project for the list.

And the list starts getting longer

Since we're talking about electricity consumption, there are also the cars. Charging them obviously represents an interesting part of the house's energy balance.

Hmm...

The cars.

Can those be integrated into Home Assistant?

Spoiler: yes.

From there, I more or less start taking inventory of the house.

The central heating? Worth checking.

The battery-powered indoor blinds installed eight years earlier? Why not.

The television, the alarm, the Google Nest devices, the phones...

Every time, the same question comes back: what can Home Assistant retrieve from this device and, potentially, what can it do with it?

The list is getting seriously long.

The funny thing is that, at this stage, I still have absolutely no idea what I'm actually going to do with all of it.

There is no carefully prepared grand home automation plan. I test things, I search, and I discover one possibility that suggests another.

Some experiments will probably turn out to be useful. Others won't. And some may never really reach a definitive conclusion.

For now, that doesn't really matter.

What about the lights?

After spending enough time looking at what can be integrated into Home Assistant, another idea inevitably comes up: lighting.

Being able to control a few plugs is fun. Being able to act on the lighting around the house starts opening up a lot more possibilities.

So I look at what's available.

Philips Hue obviously appears very quickly in my searches. But gradually replacing the light bulbs around the house with smart bulbs doesn't really appeal to me.

More importantly, there's something about certain visions of the “smart” home that bothers me.

I have absolutely no desire to pull out my phone just to turn on a light.

If someone walks into a room and presses the switch, the light has to turn on.

Just like before.

At this stage, everything I'm doing is still experimental. I don't even know whether Home Assistant will still be installed in my house a few months from now.

So there is no way I'm going to let my experiments interfere with the normal operation of the house.

Better still: if Home Assistant completely fails tomorrow, I'd like the main consequence to be:

“Oh. Home Assistant is down.”

And then the day carries on.

No lights becoming unusable, no need to explain to someone which app they have to open and, as far as possible, no essential function of the house depending on a virtual machine running somewhere.

Home automation should sit on top of what already works, not become a requirement for it to work.

With that idea in mind, the little modules that fit behind existing wall switches become much more interesting.

The switch stays where it is and works exactly as before, but Home Assistant can now control the light as well.

In principle, that's exactly what I'm looking for.

Of course, before ordering anything, it might be a good idea to check what's actually behind my switches.

So I take a few of them apart.

I look at the wiring, whether a neutral is present, the type of switch, how much room there is behind the mechanism... and I begin to understand why there are so many different versions of these little modules.

With neutral, without neutral, relays, dimmers...

My research eventually leads me to Sonoff modules. The prices are reasonable enough to order two or three and experiment without starting to equip the entire house.

And, on paper, I've checked everything I need to choose the right modules.

On paper.

We'll come back to that.

Zigbee? What's this thing now?

There is, however, one small detail left.

Some of the modules I'm looking at use something called Zigbee.

Another term I vaguely know by name without really knowing what's behind it.

A little more research tells me that it's a wireless communication protocol widely used in home automation and that, with the right hardware, Home Assistant can speak Zigbee too.

A USB dongle seems capable of doing the job.

Naturally, that gets my curiosity going.

A few Sonoff modules, something to let Home Assistant communicate with them...

Order placed.

But my first steps with Zigbee and installing those modules probably deserve an article of their own.

Because when I take a moment to look at where things stand, it becomes rather amusing.

I came to Home Assistant because I wanted to retrieve data from my electricity meter and a smart plug.

I now have my photovoltaic production integrated, a growing list of devices to explore, ideas for monitoring energy consumption, a few Sonoff modules on order and a new protocol to discover.

I still have no idea exactly where all of this is going to lead.

But one thing is becoming obvious:

the little drawer wasn't just deep. It had branches.