Editor’s Note – This is the seventh part of an ongoing series by journalist and geek Marty Winston in his quest to design the perfect smart home of the future with the best technology of today.
Our big editorial project (http://40yearhouse.com) seeks to meld being energy-miserly with avoiding major repairs or replacements for 40 years and with taking human chores away through autonomy, a level of operation beyond what you see in today’s “home automation” products.
Just as butter, cheddar, and cottage cheese all start out as milk, there are “flavors” of Bluetooth that are hard to know about because the umbrella term blurs some of the differences. We don’t need to get geeky about it, but it’s worth some attention – especially with all the new Bluetooth home automation products you’ll see hitting the market over the next few months.
So, strictly at the broad-strokes level, here’s what makes a difference.
The first time you bought a Bluetooth product, you learned about pairing, the name for the activity that sets up partnerships between devices. You would put one device into a pairing mode, have another device search for it, click on something to connect them, maybe enter a code, and forever after they would be wirelessly connected whenever they were both powered on and in range of each other.
Sometimes pairing is a good thing, like when you don’t want some other guy’s headset listening in on your conversation, or when you don’t want the speakerphone in your car tuning you in to what the truck driver next to you is saying.
There are even some home automation products that need pairing, like the electronic deadbolts you unlock with your cell phone (really, is a key that hard to find?).
But for a generation-after-next smart house, like our autonomous house (http://40yearhouse.com) editorial project build, pairing would, most of the time, be absolutely inappropriate.
You’ll get the lowdown on those no-pairing-required shades of Bluetooth in a second, but first we want to clear some clutter.
Bluetooth Confusion Diffusion
Here are some terms you’ll see dangling near Bluetooth product descriptions:
Bluetooth Smart, Bluetooth LE, Bluetooth 4, Bluetooth 4.1 and Bluetooth extended.
For our purposes, you can ignore them all. We’re going to focus on two others:
Bluetooth Smart Mesh (sometimes just called Mesh) and Bluetooth Beacon (sometimes called iBeacons or Eddystone) get the spotlight.
All Bluetooth things work like small, slow 2-way radio connections between a transmitter and a receiver; many familiar Bluetooth devices (like phones, headsets, or cars) can both send and receive at the same time.
Bluetooth Beacons are different.
The transmitter is always just a transmitter, and as a rule, it only ever transmits an identifying code. Its signal has a deliberately limited range.
A receiver responds in some way to the unique code the transmitter is sending.
Most current smart phones have the electronics necessary to receive Bluetooth Beacon signals – it’s just one of the modes of the Bluetooth electronics already inside it – but so far, you have to add apps to do anything with it.
A museum app might, for example, fetch information to your handset as you near specific exhibits. A store can tell you things about products (like promotional offers) as you near their shelves. A big hospital or campus can guide you to where you want to go based on a beacon identifying where you are now, like an indoor GPS navigator.
Beacons Bent Backwards
We found a different way to use Bluetooth Beacons – one that makes so much sense that we think once others see what we’re doing, they’ll use the same approach in their products.
Usually, the transmitter is stationary and a moving receiver responds to its position. We’re using stationary receivers and moving transmitters.
We’re putting Bluetooth Beacon transmitters in our cars, wired to only be on when the engine is running. And we’re putting Bluetooth Beacon receivers in three places: at the apron of the driveway, at the garage and at the front door.
They’re part of the logic that knows when to open and close garage doors, unlock deadbolts and tell the difference between our car or a strange car waiting at the front door.
Bluetooth Smart Mesh
Those common Bluetooth devices you need to pair set up one-to-one relationships between two partner pieces (noting that some can set up multiple one-to-one relationships, like a car that can be a speakerphone to more than one handset).
The Bluetooth Beacons we just discussed use one-to-many relationships that work without pairing.
Bluetooth Smart Mesh is a way to connect many things in a many-to-many relationship that can still recognize any one thing that’s connected to it. An example will keep that from getting confusing.
Jasco sells what they call “Bluetooth Smart” products under the GE brand; these are really Bluetooth Smart Mesh devices. Their smartphone app lets you directly control or automatically schedule anything you have plugged into a socket or wired to a wall switch.
One cool thing about that is in the way they communicate – every Mesh device can relay signals to and from every other Mesh device within its range – roughly 100 feet. You can add other products to a mesh and they all automatically interconnect – and, at the same time, extend the range of the mesh network.
AirCable is about to debut its own Mesh products, including switches you don’t have to wire in. Those switches are really like remote control buttons on the Mesh, and can recognize things like multiple taps or long presses to let multiple functions happen from a single switch. It is also about to introduce a very bright signaling blinker light.
SenseGiz is preparing coin-size Mesh sensors, so automation can get smarter and respond to things like temperatures or ambient light levels.
Mesh Pros and Cons
As we look at the various home automation protocols out there (Z-Wave and Zigbee are two examples), we like Bluetooth Smart Mesh better.
One reason is that it responds more quickly; other protocols tend to have delayed responses so, for example, clicking a switch may not turn on a light for a couple of seconds. Another is that it’s very flexible, making it a lot easier to add devices.
But it’s still relatively new, so your mileage may vary. And the landscape of products for other protocols is home to a wider population of products.
Also, with the all-directions-bucket-brigade of Mesh, it’s efficient and reliable for small amounts of data but huge amounts can overwhelm it if you want it all relayed too quickly.
That impacted our plan. We have 30 sensor beds that wanted to communicate what was collectively thousands of measurements ten times every second – we had to shift that communication to wired Ethernet. Something tells us your demand won’t that high, so Mesh should prove easy, speedy and reliable for you.
Our Blue Tunnel Tweak
We’re doing one more trick with Mesh that you won’t use, but we’ll share anyway.
A firewall deliberately blocks our entire home control network from the outside internet. But we need to fetch specific data (like weather forecast info) from the outside internet. So we are putting one and only one of our Raspberry Pi controllers on a different connection that does allow connecting to the outside. And the only way it can connect to our other automation controllers is over a Bluetooth link.
Enough of the Blues
We should probably do an installment about how we approach networking, one on backups and maybe one on thermodynamics (and we don’t mean theoretical).
Comment here on the things you’d most like to see covered – and if you need inspiration – feel free to visit http://40yearhouse.com to learn more about what’s involved.