Everything you need to know about Apple TV and HomeKit

Posted by Michael
Posted in Okategoriserade

Inside your home, you control your HomeKit accessories with Siri. Outside your home, Siri talks to your Apple TV.

Your third-generation Apple TV may be getting a bit long in the tooth hardware-wise, but it stil has some skin in the new software features game: Its recent 7.0 update included support for extending communication with your HomeKit accessories outside your local Wi-Fi network.

I've had a ton of people ask me about this feature since HomeKit products officially started rolling out last Tuesday, so here's the deal.

It's not (nor will it be) a HomeKit bridge

A HomeKit extender does not a HomeKit bridge make: Just because your Apple TV can talk to HomeKit doesn't mean it can link your Hue bulbs and Nest thermostat into that framework.

First of all, HomeKit hubs have to be built with certain bluetooth and Wi-Fi specifications, and I suspect that the 2012 Apple TV may not have the hardware for such a venture. On top of that, for the box to be a HomeKit bridge, it would need to develop secure handshakes and APIs for every third-party accessory out there — no easy feat.

I'm not saying that there's never going to be a future Apple TV that also acts as a HomeKit bridge, but such a thing is nigh-impossible for your current Apple TV.

So what does the Apple TV do for HomeKit?

By default, HomeKit is limited to your personal Wi-Fi network: All handshaking and Siri commanding happens within those boundaries. But your Apple TV — in combination with your Apple ID — gives your iPhone or iPad a way to securely talk to your HomeKit devices even when you're outside the house.

It does so using a under-the-hood mixture of iCloud Keychain and HomeKit frameworks. Say you're on LTE: You press the Home button to pull up Siri and give the command "Turn on the lights." Without an Apple TV, that command goes nowhere — Siri replies with "I can't do that."

With an Apple TV on your home Wi-Fi network, however, that command travels over cellular data to your set top box, where it handshakes using your Apple ID. "This is the owner of this HomeKit network," Apple TV then says to your installed HomeKit bridge. "Here's a command from them." The HomeKit bridge then executes the command, and the lights in your home pop on.

Now, if you're doing this on LTE sitting in front of your lights, you're going to see a slight delay between giving Siri the command and the command actually happening: This is because of that extra handshake that happens between the Apple TV and the HomeKit bridge; normally, when you're on Wi-Fi, your commands go directly to the bridge, then to your compatible accessories.

But I'm going to hazard a guess that 90 percent of commands given outside your Wi-Fi network won't be to turn on a light right in front of you; they're going to be to unlock your door, turn up the thermostat, or turn on the lights from your car. By the time you get to your door, the command should have been executed with time to spare.

There is one other limitation to the Apple TV's relay: It currently only supports commands from the owner of the HomeKit home. This is because the Apple TV can only be logged in to one iCloud/Apple ID at a time.

For instance, say you created a HomeKit network under john@icloud.com and also added sarah@icloud.com as an additional user. You're also logged in as john@icloud.com on your Apple TV. Sarah can use Siri to activate HomeKit when she's on your Wi-Fi network, but once she leaves the house, she'll be unable to issue commands. Because your Apple TV is only logged in to one account, it can only authenticate commands from that one account.

I'm hoping this will change with a future Apple TV software update — say, by adding a HomeKit section to Settings with a list of your additional users. But because HomeKit currently requires iCloud Keychain to secure the command, I wonder if those additional users will have to log in to your Apple TV, rather than just you listing their screen names. The security issues involved may make it a tougher nut to crack than it appears at first glance, and Apple appears very committed to keeping HomeKit secure.

Here's how to set up your Apple TV with HomeKit

If you have HomeKit-enabled accessories in your house and want to hook up your Apple TV so that you can give Siri commands outside your network, it's an easy process. Here's how you go about it.

Make sure you've set up rooms and zones for your accessories with Siri.
Turn on your Apple TV.
Open the Settings app.
Click on iCloud.
If you're currently logged into iCloud, log out and log back in; otherwise, log in with your iCloud ID. If you're already logged in with iTunes, it may prompt you to log in with the same ID.

Give it a few minutes; after that, you should be able to use HomeKit commands with Siri even when you're not on your local Wi-Fi network.

If you can't get it to work after ten minutes or so, try restarting your Apple TV and repeating the above steps. It took me a couple of logouts/logins before my Apple TV successfully started routing Siri HomeKit commands.