[From the last episode: ConnectionsThis refers to some kind of electrical connection. It might be through a network cable, a cable connection, a wireless connection, or a phone - just to name some options. The connection might be to the internet or to some other local device. to the cloudA generic phrase referring to large numbers of computers located somewhere far away and accessed over the internet. For the IoT, computing may be local, done in the same system or building, or in the cloud, with data shipped up to the cloud and then the result shipped back down. aren’t always useful – and they’re occasionally frustrating]

Before we look into how the different major IoTThe Internet of Things. A broad term covering many different applications where "things"  are interconnected through the internet. players work, there are a few more things we should get under our belts. This week, we talk about hubsA piece of electronic equipment that gathers separate related things together. A network hub, for instance, might bring together the individual network connections of multiple local users. A sensor hub brings together sensor data from multiple separate sensors for possible combination. Or, more specifically, a device in the home (or elsewhere) that acts as a central point connecting a variety of smart-home (or other) devices. The devices talk to the hub; the hub talks to the cloud..

Hubs

We’ve talked about the four central aspects of the IoT: sensing, communication, computing, and actuatingA way of controlling some device electronically. It might turn the device on or off or change a setting or property or do any other thing that the device is capable of.. We’re focusing here on computing. In particular, we’re asking the question, where does the computing happen?

We’ve talked about computing happening in the cloud; that’s one obvious place. And we talked about the possibility of having a local serverA computer with a dedicated purpose. Older familiar examples are print servers (a computer that controls local printing) and file servers (a computer used for storing files centrally). More modern examples are web servers (the computers that handle your web requests when you use your browser) or application servers (computers dedicated to handling the computing needs of a specific application). Servers are often powerful, expensive machines since they have to handle a heavy load. handle some of it – that fog thing. Frankly, we haven’t mentioned that the devices themselves can do some computing. But in that last case, the devices have very little computing power – more power means more expensive chipsAn electronic device made on a piece of silicon. These days, it could also involve a mechanical chip, but, to the outside world, everything looks electronic. The chip is usually in some kind of package; that package might contain multiple chips. "Integrated circuit," and "IC" mean the same thing, but refer only to electronic chips, not mechanical chips., which means a more expensive device – and no one wants that.

So most of the computing happens at one of those other two places. And we talked about using a server for fog computing as being mostly an industrial thing. Which, if we’re really talking about a server, it probably is.

But in the home IoT world, we have hubs. (From a networkA collection of items like computers, printers, phones, and other electronic items that are connected together by switches and routers. A network allows the connected devices to talk to each other electronically. The internet is an example of an extremely large network. Your home network, if you have one, is an example of a small local network. standpoint, it might also be called a gatewayA piece of electronic network equipment that takes a local network and gives it access to the internet. Your cable modem, for instance, might act as a gateway., but, for homes, “hub” is more common.)

What the Hub Does

A hub has a couple of roles. For one, it can act as the arbiter of all the other devices – the supervisor, if you will. It registers and connects all the devices in your home together (or at least the ones that can talk to the hub – yeah, this is a perfect place where walled gardens and ecosystems are built).

It can also handle some of the computing locally, without going to the cloud. Exactly what to do locally isn’t something you can generally decide on – whoever made your device handles that. It’s part of that thing of trying to learn whether a device you’re considering has to be connected to the cloud in order to work.

This means that you can have one device take action based on some other device. For instance, you might have a light sensorA device that can measure something about its environment. Examples are movement, light, color, moisture, pressure, and many more. that notes when it’s daylight, and then turns off certain indoor lights. (OK, so that’s been something you can do for decades, but it’s a classic example of one device – the light sensor – affecting another – the lights.) The hub allows that to happen.

Your hub will presumably have some way for you to interact with it. It might be via a smart TV, or perhaps through your phone. That’s how you can search for apps associated with your devices. And, in principle, you could purchase additional apps that let the devices you already have work better together.

If you’re more technically minded, you may even be able to write your own scripts that say, “If this thing over here happens, then do that thing over there.” Getting your devices to play together like a well-tuned orchestra.

Hub Variants

Theoretically, having a hub would make it less necessary to connect to the cloud, since you can do more locally. Practically, however, a home hub is probably going to be from a large IoT provider, and they’re going to want you to connect to the cloud.

A hub can take on a few different looks. Most typically, it’s just a box you put into your house, just like a routerAn electronic box that helps steer data on a network. For instance, you may have one in your home connecting your phone and computer and other devices to each other and to the internet. The data itself has information about where it's being sent; the router uses that information to send it in the right direction. At a really basic level, you can think of a router and a switch as being the same thing. If you want to get more technical, a switch creates a local subnetwork, and the router connects multiple subnetworks (or multiple networks).. Or it could be in your TV. Or it could be embedded in a speaker, as we’ll see in a few weeks.

In theory, you could even use your phone for computing. For that to work, your device maker will need to have created an app that you download that knows how to interact with your device. Many devices will have apps for your phone, but they would typically be for communicating with the cloud – the phone acts kind of as a remote control, while the computing work is still done in the cloud.

Going Hubless

Does everything require a hub? No; some devices might be able to connect directly to the internet. They would do that through your in-home network – most likely WiFiA common type of wireless network used to connect computers and phones to each other and the internet.. Your router and internet modemA piece of network equipment that converts data into a format that can be transmitted. Old modems sent the data on a phone line; modern cable modems send the data across a cable connection. It stands for "modulator/demodulator." then handle the restA way of programming that has evolved out of web programming, and it’s more abstract than other older languages like C.. Again, this isn’t a decision you make with your device; it’s a decision made by the designer, and your part of the decision lies in figuring out which device to purchase: one that takes a hub or one that doesn’t.

Without a hub, you probably have less privacyRefers to whether or not information gathered about your usage of IoT devices by authorized people can be made public, or shared with others, without your consent. Different from (although related to) security, which protects such data and devices from access by unauthorized people. Different from privacy, which is more concerned about use of data by authorized people. on some things (at least in theory – it depends on how the makers design things) because, with a hub, some trafficRefers to any kind of electronic message -- email, web request, streaming video, or anything else -- that travels over a network. stops within the home. (That assumes that the hub isn’t regularly radioing everything to the cloud…)

Some things you try to do may also take longer without a hub, since your requests have to go all the way to the cloud in order for the device commands to come all the way back. If you do that with a hub, it’s local, so it goes faster. For instance, a door lock is something you might want to do with a hub, since you need it to work if the internet is down, and you might want the lock to respond as quickly as possible.