Although not many people can see the need for having their smart fridge connected to the Internet, most people will find the ability to remotely control lights, security cameras and other home appliances very useful.
If you are thinking about adding smart devices to your home then this guide to smart homes and home automation will give you a good basic understanding of how smart devices are connected and how they are controlled.
What is Home Automation?
Internet of Things vs Home automation
Home automation is one of several areas of the IOT (internet of things), and is often called Home IOT.
Home automation or domotics is building automation for a home, called a smart home or smart house. It involves the control and automation of lighting etc –Wiki
There are three distinct levels of home automation.
The ability to view status of systems i.e
- What is the temperature?
- Is the door locked?
- Is The Light on or off
The ability to change the state of a systems i.e
- Turn up the heating.
- Lock the Door
- Turning the light on or off
The ability to change the state of a system automatically in response to an event. i.e.
- Turn on the heating if the outside temperature falls below a certain temperature.
- Turn the lights off when no one is a home.
Currently most smart home systems are at the control level.
Smart Home – Automation System Components
A home automation system will consist of
- End Devices like switches, sensors,lights,locks etc
- Connection devices like hubs and Gateways.
- A Network or networks e.g. Wi-Fi, Zigbee etc
- Internet connection – maybe optional
Local Control And Cloud Control
All homes should be able to be controlled locally from within the home.
This doesn’t mean that they should have manual switches, but that they should be controllable across a local network.
They should also IMO be controllable and fully functional without an Internet connection.
In other words if you loose the Internet connection you should still be able to turn your lights on and off.
Unfortunately not all systems will operate without an Internet connection. This article is worth reading.
As a General rule of thumb Zwave and Zigbee networks and devices will operate without an Internet connection.
Wi-Fi devices will generally require an Internet connection.
This reddit discussion is worth reading.
The Role of the Cloud In Smart Homes
Many Internet devices especially Wi-Fi devices are dependent on an Internet connection, and cloud services to function.
Generally when you set up these devices you register them with the manufacturer on a cloud service.
They can then be controlled via an App on a smart phone, Alexa etc but will require an Internet connection to function correctly.
Although these devices are easy to setup and operate they are useless without an Internet connection.
IMO the Internet should represent an alternative way of controlling devices, and not the only way
Smart Home Networking- Wi-Fi, Zwave, ZigBee,Thread, Bluetooth
These are all wireless protocols found on home networks.
Current home networks used for connecting computers and other devices to the Internet are Ethernet and Wi-Fi based.
They also use TCP/IP as the networking protocol.
Logically home automation devices and products would just attach themselves to this existing network which would mean that they also would use Wi-Fi and TCP/IP.
However early home devices like sensors, and door locks were not mains powered, and so required low power consumption.
Therefore Wi-Fi wasn’t considered a suitable protocol for use in these devices, hence the development and use of Zigbee (Philips Hue) and Zwave wireless standards, and other proprietary protocols in home automation products.
Devices using ZigBee and Zwave form their own network independent of the existing home Wi-Fi network ,but can be connected to the existing Wi-fi Network using a suitable hub or gateway.
Thread is a newer standard sponsored by Google and uses IP networking ( zwave and Zigbee don’t) but uses 6lowpan and not Wi-Fi.
The Diagram below shows an example network:
There are several different types of end device:
- Devices that work using a remote control like a TV and cannot be connected to a home network.
- Devices that use Wi-FI and TCP or UDP over IP as the networking protocol. These connect directly to the existing home Wi-Fi network and are usually controlled via an App on a smart phone. They can also be controlled via a hub like Amazon Alexa. Generally require an Internet connection to operate.
- Devices that that use Zwave or Zigbee will require a hub to connect to the home network and the Internet. Generally operate without an Internet connection.
- Devices that use proprietary protocols like Mi|home
Hubs and Gateways
If your end device supports Wi-Fi then it can connect directly to you existing home Wi-Fi network, if it uses Zigbee,Thread or Zwave or other protocols then it will require a hub of some sorts (diagram above).
However hubs can perform other task besides interconnecting products using different protocols.
They can also provide Gateway functions e.g. converting your sensor data to MQTT.
Smart hubs will generally provide a User Interface that allows you to manage the individual devices, and to set up automation rules.
This can be via an App on a smart phone or tablet or web browser.
TCP/IP Hubs can be located on the Home network or on the Internet.
Amazon Alexa is an example of an Internet based hub that is becoming very popular.
Smart Home Control Protocols
Currently the main control protocol used to control smart home devices is HTTP.
HTTP is the protocol used for accessing website like this one.
Because this protocol is being used you can control many smart home devices using a web browser.
However HTTP is not the main protocol for IOT (Internet of things) devices.
The choice here is MQTT (MQ Telemetry Transport ) and this will also become the main control protocol for home automation.
Many smart home devices will be bi-lingual in that they will support both protocols.
Controlling Smart Home Devices with a Smart Phone
Because of the popularity of smart phones, most smart home devices and systems can be controlled using an App on a smart phone or tablet.
However devices from different manufactures will have a different App, and going back and forth between Apps is not very convenient.
Below is a screen shot from my Tablet showing the Apps to control several Wi-Fi smart devices from different manufacturers.
Not only is it very inconvenient to keep switching between Apps, the Apps can’t talk to each other, and you also need to install them on all devices that you use to control these devices.
However most of these devices can also be controlled by a hub like the Samsung Smartthings, Amazon Alexa or an home automation system like homeassistant..
Generally when you have several smart devices, especially when they are from different vendors then using some form of Hub/automation system to combine them is the best option. See hubs,Gateways and Home automation Systems
Voice control using devices like Amazon Alexa are becoming more popular, and are much easier to use.. Almost all devices being introduced today are being designed to work with Alexa and Google Home.
- Stack exchange-Do I need a hub for some devices?
- Can Zigbee be used without a hub
- See Toms Guide-Home automation primer –
- Z-Wave Basics Notes and Resources
- Zigbee Basics Notes and Resources
- Introduction to Sonoff Switches
- Setting up the Sonoff Tasmota MQTT Switch