Parts of a Smart Home
Smart homes are unique entities. Each owner goes out to create solutions to their own problems, but even the same problem can have multiple solutions. Four categories were picked in an effort to generally explain the different parts of a smart home. Some devices may fall into multiple categories, or may be a category unto themselves. However, for this purpose, the categories chosen are Smart Devices, Gateways, Interfaces, and Servers. For each part of the smart home we discuss, examples will be provided. Then, we’ll go over how they all fit together.
Parts of a Smart Home
Smart Devices
Smart devices seem like the natural place to start in explaining smart homes. A smart device is the one that will do the “thing” you want to do. You can make a smart light bulb turn on and change colors. You can make a smart vacuum clean up when you go to bed. You can make a smart camera turn on when you leave the house. Whatever “thing” you want done, is likely done by a smart device.
Smart Device Types
- Switches
- Plugs
- Lighting
- Speakers
- Cameras
- Appliances
- Accessories
- Sensors
Gateways
A gateway (also referred to as a hub, controller, or bridge) is the device that communicates with your smart device. Infrared, ZigBee, Z-Wave, and Bluetooth are different methods of communicating with smart devices. Typically this is done through a hub that can communicate with the devices you want to control. You may also see smart devices that use WiFi advertised as being “hubless.” I would argue that your WiFi at home is the hub because it “speaks” WiFi and can communicate with these devices.
Gateway Communication Types
Interfaces
If a hub is the device that can communicate with a smart device, then an interface is how YOU communicate with the smart device. This is where smartphones, voice assistants, and sensors reside. You can tell Alexa to turn off the lights or change the temperature. You can also make this happen by using your smartphone and a device’s app. Sensors can also be used to interface with your smart home.
Interface Options
- Smartphones
- Voice Assistants
- Sensors
- Door/Window Sensor
- Motion Sensor
- Button Sensor
- Leak Sensor
- Automations
Servers
Servers are where all of the smart home “thinking” is done. Many devices today utilize cloud servers to do most of this offsite. If you’ve ever asked Alexa a question while the internet was out, you know what this is like. Alexa works by taking your speech, sending it to its servers at Amazon, and returning information or completing a command. At Smart Home Hobby, I utilize Home Assistant as my server. This is a software that runs locally, so you don’t have to rely solely on other company’s servers to be running in order for your smart home to work.
Server Examples
- Home Assistant
- Amazon Server
- Apple Home Kit
- Cloud Servers
Fitting Them Together
Below are some diagrams to help you visualize how the parts work together.
Generalized Connection Diagram
Here is a general diagram of how your smart home devices may work, depending on what you have. You tell your devices what to do (through the interface), that command is sent through the server (either locally or in the cloud), the command is received by the gateway who then tells your smart device what to do.
Sonoff Smart Plug Cloud Control
There’s 2 main ways that most people use cloud control to control devices. Through the device’s app, and through a voice assistant.
In this diagram the smart plug is being controlled from the eWeLink app, using cloud control. This is how it works when you control a device while you’re away from home. You pass a command on to the eWeLink app on your phone, that command is sent to eWeLink’s servers. After that, the eWeLink servers communicate to your plug via the WiFi connection.
This diagram shows how a Sonoff smart plug works using Alexa, which also utilizes a cloud. This example shows how two different servers might be used to control your devices. You pass the command off to Alexa. The command is sent for processing to Amazon’s servers. Amazon’s servers use your eWeLink app login credentials to connect to your smart plug. The command is sent through WiFi to toggle the device.
Sonoff Smart Plug Local Control
Sonoff smart plugs can also be controlled locally, through the app. As long as the smartphone and smart plug are connected to the same WiFi network (even if there’s no internet connection), the device’s state can be toggled. Here, you can see how the command goes from the app, straight through the WiFi to the plug. Local control should be the ultimate goal when building your smart home because then you do not need to rely on any outside servers for the devices in your house to work.
Conclusion
A smart home is more than the sum of its parts. It’s in how you use them, together, that matters most. For the best smart home experience, you will want to embrace local control. Home Assistant is an open source software that allows you to integrate devices from different manufacturers and ecosystems and control them locally. To get started, you will first want to install Home Assistant on a Raspberry Pi.
