Which protocol to pick for your smart home

I was talking to a buddy the other day and I had passed a comment about how Google blows Alexa out of the water in the voice assistant category but somehow our conversation quickly derailed into smart homes.

“You mean you allow those devices in your home? They listen to everything you say! ” - he exclaimed!

My response to him was something along the lines of the smart assistants having to have an earful of my son calling his daddy silly because of my many antics or him constantly asking for pizza - which is true, but it’s partly the reason why I’m not so concerned. I will share more about protecting your smart home in another blog hopefully soon but this is not what I intend to write about now.

I find that there are generally three groups of people when it comes to smart homes- those that are for it, those are against it and then we have the “What’s a smart home” group. Hopefully, I will be speaking to members of all three groups with this post.

There are a few options when it comes to the protocols that these devices operate on and I will write a blurb on each of them which will shed some light on why I ended up with Z-Wave (Spoiler alert!). A few points that we need to understand before we move along. Warning ⚠ Probably unnecessary nerdy paragraph below:

• All smart homes devices use some form of radio frequency - which is just really low radiation that sits on the lower end of theelectromagnetic spectrum
• All the “guys” on this spectrum have the attributes of wavelength and frequency. So if you have a high frequency then it means there is the short wavelength and conversely, if you have a long wavelength, it means you have a low frequency

Keep the info handy, you will need it for your next physics quiz. 😉

Wifi

This is by far the most popular protocol smart devices operate on. A plethora of devices that the big box stores carry work on Wifi which operate on standardized 802.11N protocol

Wifi operates on two main frequencies - 5GHz and 2.4GHZ. The frequencies individually can be described as a double-edged sword. Remember, my blabbing about frequency not so long ago - good! The low frequency of 2.4GhZ will be able to pass through walls and floors much easier because of the lower attenuation but will be slower than the 5GHz which can transmit data faster (but cannot travel long 😟 ). By the way, all the communication will be to an access point (commonly referred to as router because they are sometimes bundled) and then will transfer some data to a cloud or local server of some sort (think Google talking to your access point, which then communicates over the internet with Google servers).

Unfortunately, that’s not all the bad news when it comes to wifi. Most of the devices used in the home share the same 2.4GHz frequency space! I’m talking about all those iPads, phones, Bluetooth devices, cordless phones, microwaves…etc! This causes a congestion which leads to interference. Your devices may not be as snappy as they should. This is why 5GHz is the preferred option if your device supports it as it’s faster and also will not contribute to less interference from neighbors.

There’s also the issue with data privacy, especially with wifi-based devices. I’ll talk about this in detail in a subsequent post but having your IoT devices talking directly to your access points may make them more exposed to the outside world.

But on the brighter side, Wifi based devices are much cheaper and easily accessible at your local BestBuy and the smart home sections in most hardware stores. TP-Link, Wemo, Leviton and Teckin are some popular brands od smart switches you will see on the more commonly.

Zigbee

As I hinted earlier, Zigbee also operates on the 2.4GHz frequency. So, it joins your other wifi-enabled devices in your household in the congestion war. Unlike WiFi, it talks to a hub that supports the protocol and then possibly to the cloud (or local server) which will send you a push notification for example

The other downside of Zigbee is that it’s an open wireless standard. Companies have the freedom to implement Zigbee in their way. Hence, Zigbee devices from different companies could have trouble talking to each other! This is evident when for example, you try to connect a Phillips hue bulb (which operates on the Zigbee protocol) to a Samsung Smarthings hub. The hub recognizes it alright, but there is not much information sent between the two devices as it only recognizes it as a thing.

But hey there are some good things about Mr. Zig, well kinda. Zigbee devices can form a mesh network with their other friends (who are not battery powered) you have in the home and use that as hop points to send a message to the hub. This is useful when you place your device far away from your hub and want to extend the range. The kinda part I alluded to earlier, well because Zigbee devices have no standard when it comes to devices, multiple mesh networks could form based on their similarity in implementations and hence cause another interference.

Z-Wave

Unlike the other two, Z-Wave operates on a lower frequency based on RF433 protocol. It’s a frequency of 0.9GHz.

Like Zigbee, Z-Wave also communicates only to a hub that supports that protocol. It can also form a mesh network which helps to carry the signal to your hub if it’s further away from it

Licensing Z-Wave is not a free for all. It’s a proprietary technology by Sigma Designs, whose parent company Silicon Labs are the sole producers of all Z-Wave chips.

I guess you can say this makes it more standardized but it also drives the prices high. Z-Wave devices are the most expensive among the three because of the fees companies have to pay to get a chip and license their devices and get the Z-Wave certified sticker!

Conclusion

A few weeks ago, it was announced that Amazon, Apple, Google, Zigbee and a few others were forming an alliance called the Project Connected Home over IP. This new royalty-free standard will allow compatibility among smart home products with security at the forefront. Imagine a world where when someone rings your Ring doorbell (owned by Amazon) can broadcast a live feed to your Google Home Hub display and then tell your Apple HomePod to broadcast a message that someone is at the door - all without writing any custom automation or using IFTT. You wouldn’t have to stick to one ecosystem any longer! What a time to be alive. Till then…

I chose Z-Wave for 3 main reasons though it was slightly pricier than the other two

• There is some standardization and all devices are cleared by the Z-Wave Alliance. So they can easily form a mesh network.
• It operates on a lower frequency and avoids all the congestion over the 2.4GHz frequency.
• I wanted to reduce the length of the “line” of multiple devices waiting for the turn to talk to my WiFi access points.

Also, very recently, it’s been announced that Z-Wave is going fully open source. I feel like it’s because of the heat from the Project Connected Home over IP, but they deny that.

I think there is still a lot of volatility in the space and it’s about time things settled down and became standardized. Till then, we play the waiting game and see how things play out