On Monday (two days ago at time of writing) I set up my first foray into the world of home automation. I purchased two devices from the local Apple Store, both made by Elgato; the Eve Room, and the Eve Energy. The former is an air quality sensor that reads humidity and temperature as well as volatile organic compounds (broadly the things that trigger allergies or breathing difficulties in some people) and the latter is a smart power socket.
My initial interest was the sensor. I love the health app on my iPhone, and the various data that are collected by the smart scale in the bathroom (when I remember to use it) and my Apple Watch. The Eve Room kind of does the same data collection for the health of my home environment. I added the power socket so that I could use that data to trigger some level of automation — initially using the room temperature to turn the large fan that lives in the corner on or off when it's warm or cold enough. I have also wanted an opportunity to play with the Home app and Apple's HomeKit for a while.
The Elgato devices are bluetooth controlled, so they need to be in bluetooth range of a HomeKit Hub (either a recent generation Apple TV or a recent generation iPad configured as a Hub) which may be a limiting factor in their placement but also does mean that they're not on your wi-fi where they could potentially cause trouble. HomeKit requires a level of security that means you shouldn't have to worry about internet-of-things based network vulnerabilities but as these particular things don't even live on your network it is not a concern.
The Elgato Eve app for iOS is a fully featured HomeKit app and virtually all of your settings are shared between that and the Home app on iOS. The Eve app exposes some additional data from your sensors, but they're pretty interchangeable. You do not need the Eve app for anything, and can add and manage Elgato accessories entirely from the Home app on iOS. Keep it around though, it's able to do some tricks with your sensors that aren't exposed through the Home iOS app.
Siri integration is really cool. I can ask her what the temperature or humidity is and almost always get an immediate response. Once or twice I've had to ask again as it's seemed that the sensor didn't reply fast enough for Siri's liking and she responded that the sensor was offline when it wasn't. What really feels like science fiction though is asking Siri to turn the fan on and off, which I'm sure will get old one day but right now it's somewhat gleeful.
As of today, however, we also now have almost a full suite of smart bulbs, adding lighting control to our home automation repertoire. We opted for Ikea Trådfri largely based on it's more reasonable cost than competing systems. Ikea's smart lighting only gained HomeKit support on the first of this month through a software update, and unlike most of the competition the bulbs are predominantly white spectrum (they do offer one model of colour spectrum bulb). Ikea also offer a collection of sensors: motion sensitive wireless dimmer switches, motion detectors, and a simple, wireless remote control. None of these are HomeKit compatible, so they can't be used for any purpose other than controlling the lighting. This doesn't really matter in the case of dimmers and remotes - they serve as dumb switches for those moments when a touchscreen or Siri are inconvenient. The motion sensors would be a great addition, however there are excellent alternatives available that will work fine (including from Elgato).
Trådfri uses a bridge unit connected to your router, and connects to other Trådfri devices by a wireless protocol called ZigBee. The bridge is physically cabled in to the router, so nothing is exposed to wi-fi. As I mentioned HomeKit mandates a solid level of security, but not having an additional dozen or more devices on your wi-fi is going to be good for speed and stability. So far the bulbs have maintained connection flawlessly.
If you're setting up your Trådfri lights with the intention of using the Home app on iOS then you do not necessarily need to use the Trådfri app itself beyond the generation of the bridge's HomeKit code. Any configuration done in one is not reflected in the other. If you want to add Ikea dimmers and remotes however you'll need to keep the Trådfri app organised. You can get buttons and the like from other manufacturers that are more versatile and HomeKit integrated.
We will need to add a couple of motion sensors to make the most of lighting automation, but we already have set up a couple of scenes for various activities; dimming and changing the colour of lights in the living room for movie watching. There's also some basic automation: the entrance to the apartment is a small windowless room, and now whenever one of us arrives home the light is automatically switched on for five minutes. I want to add some rules such that motion in one of the bathrooms at night will automatically turn the light on low for ten minutes, but do nothing during the daytime. Setting these things up is pretty easy, once you have the pieces in place.