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The so-called "Internet of Things" is an ever-expanding universe of connected devices, and with big players like Apple, Google, and Amazon in the mix, it's growing faster than ever. The dream is that everything will work with everything, making it easy to build the specific smart home you've got in mind. The reality, though, is that the walls are already starting to come up.

For instance, say you're an iOS user who owns a Nest thermostat. You'd like to expand your smart-home setup -- does it make more sense to go with Nest-compatible gadgets, or with gadgets that play well with Apple HomeKit, the smart-home protocols built into your iPhone's operating system? There isn't much overlap between the two -- your HomeKit gear likely won't work with Nest, and your Nest certainly won't work with HomeKit (or with Siri.)

The answer to that question and questions like it largely depends on what you want out of your smart home. It's also the exact thing we're tackling right now as we build out the connected-home setup at the CNET Smart Home, our living lab for building, testing, and experiencing the home of the future -- for better or for worse. Here's what we've learned so far.

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The (fractured) state of the smart home

If you're looking to smarten up your home with anything more than a couple of devices, then you're going to want to understand what does -- and doesn't -- work with what.

On Apple's end, there's HomeKit: A set of smart-home-specific protocols programmed directly into the software that powers iPhones, iPads, iPods and the Apple Watch. The idea is that HomeKit gives device makers a set of standards to build around -- those that comply with Apple's way of doing things will enjoy seamless integration with Apple's mobile products, with other HomeKit-compatible gadgets, and with Siri, Apple's voice-activated artificial-intelligence assistant. The downside is that it's an approach that leaves out Android users -- and that many of those HomeKit gadgets won't work directly with non-HomeKit gadgets.

With Google, everything is more-or-less centered around the Nest Learning Thermostat from Google-owned Nest Labs, with new products joining up by way of the . Products willing to fall in line with Nest -- and extend the thermostat's usefulness -- get to piggyback off of its popularity, and many of them integrate directly into the Nest app. Google's upcoming efforts with Weave, a smart home mesh network designed to improve device-to-device connections, should give gadget-makers something else to fall in line with, too (new smart locks from Yale are already promising to do just that).

Beyond those two, you'll find smaller control platforms like Insteon , IFTTT , Staples Connect and SmartThings , which was acquired by Samsung last year. The degree to which each one will work with third-party gadgets varies, as does the extent to which they'll work within the connected-home ecosystems of larger players like Apple and Google. Insteon offers a HomeKit-compatible version of its hub , for instance, while Google Weave integration seems like a strong possibility for SmartThings, given Samsung's involvement with Google's previous efforts at improving smart-home communication.

There's also the Amazon Echo smart speaker, which offers voice-activated control of certain smart-home gadgets by way of Alexa, the cloud-connected AI assistant housed within. Its popularity is on the rise, and it's continuing to work with more and more devices, positioning Alexa as a potential rival to Siri.

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The state of the CNET Smart Home

If your head is starting to spin after those last few paragraphs, I can't say I blame you. Sorting out what works with what is one of the key smart-home headaches right now, and it makes jumping in with connected-home tech a lot more intimidating than it probably ought to be.

We aren't letting that stop us from building out the CNET Smart Home, though -- and we aren't sticking with a single smart-home platform, either. As of now, we've installed a SmartThings Hub, HomeKit-compatible Philips Hue light bulbs, Nest thermostats, and two Amazon Echos as core components of our system. The idea is that we want a fully functional smart home where we can test out as great a number of devices as possible, and that means ignoring a lot of those walls in the Internet of Things.

Perhaps surprisingly, the result has been a lot less chaotic than you might expect. None of the devices we've installed prevent any of the other devices from doing what they need to do. Take our color-changing Philips Hue bulbs, for instance. Right now, they work with HomeKit, they work with Nest, they work with Amazon Echo, and they work with SmartThings. Step into the CNET Smart Home, and a SmartThings-compatible motion sensor can trigger the Hue bulbs to turn on. From there, you could pull your iPhone out of your pocket and tell Siri to turn them all blue, then head into the kitchen and ask Alexa to turn them all off. If a Nest Protect smoke detector detects a carbon monoxide leak, the lights will flash red. All of it works at the same time, under the same roof.

IFTTT

We've also filled in some of the gaps by using the free online automation service IFTTT. It's been especially handy with our Nest thermostats. By tapping into the Nest IFTTT channel, we can sync them up with other IFTTT-compatible devices that don't work directly with Nest otherwise -- the Belkin WeMo Light Switches that control our outdoor lighting, for instance.

Still, there are plenty of limitations. We're nowhere close to having a unified setup that we can program from a single app or control from a single voice-control platform. With its emphasis on standardized controls and Siri support, HomeKit seems like the best bet to get us there, but there still aren't enough gadgets to cover the kind of wide-scale connected home we're trying to build. Plus, not all of us use iPhones here.

Perhaps that's the true takeaway -- no single smart-home platform can claim to do everything, at least not yet. If you want a setup that's truly comprehensive, you'll need to find ways of navigating around those walls, even if it means using multiple apps to configure the way you want everything to work. That's a lot more workable than you might think, but if it's still a deal breaker, then your best bet is probably to wait and let things continue to develop before buying in on a big scale.

The better approach might be to temper your whole-home automation expectations and prioritize automating the things in your home that truly matter to you -- lights, security, voice control, etc. Whatever it is, get those devices up and running first, then build out from there with compatible gear that fits in with what you want out of your smart home. After all, the most important question of compatibility in the connected home is whether or not any of it is compatible with you.