With home automation (also known as domotic or smart home technology) becoming increasingly prevalent, there is now a bewildering variety of different protocols in use by developers. Each one has its advantages and disadvantages.
Early home automation technology relied largely on wired systems using protocols such as UPB (Universal Powerline Bus) and X10, protocols based on signals sent along the home’s power lines. These ingenious and effective systems are somewhat in use today — notably, the Insteon family of lighting devices uses X10 technology — but are rapidly being supplanted by various wireless protocols that don’t rely on physical connectivity.
The chief advantage of Wi-Fi as a home automation protocol is that most homes nowadays have a Wi-Fi network. However, Wi-Fi would not be my first choice as it was not developed with home automation in mind. Its power efficiency is very poor and it requires more processing power than protocols specifically developed for home automation. That said, its ubiquity and relative accessibility make Wi-Fi popular with domotic developers.
Created in 2005, ZigBee is one of the earliest protocols developed purely for wireless Internet of Things (IoT) devices. It’s now somewhat in decline, but remains in widespread use. ZigBee is optimised for power efficiency rather than range; under ideal conditions it can deliver 100m in the open air, but typically achieves less. One big advantage of ZigBee is that it it supports mesh networking, where each device or node in a system can communicate with all the other nodes, increasing its versatility and potential range.
Like ZigBee, Z-Wave was developed to support the low-power, low-bandwidth needs of domotics. It is currently the most successful IoT protocol: over 100 companies incorporate Z-Wave into their products, and there are over 1000 Z-Wave enabled devices. Advantages of Z-Wave include its low power and processing requirements, and the fact that it uses lower radio frequencies than other protocols. This protects Z-Wave devices from interference due to Wi-Fi and Bluetooth signals. Z-Wave also uses a mesh networking topology, allowing its range to be extended significantly.
Bluetooth Low Energy
Bluetooth Low Energy or BLE differs from standard Bluetooth in that it is optimised for short bursts of low-power communication instead of data streaming. Developed with mobile devices very much in mind, BLE allows devices to be accessed directly via smartphones and tablets rather than requiring access through gateway. As BLE has become more popular, chips have come down in price and it’s now an inexpensive option for developers.
Thread is an IP (Internet Protocol) based wireless domotic technology developed with a view to unifying various smart home applications under a single versatile protocol. Thread’s IPv6 capability allows devices to be networked and controlled via the Internet with ease. Thread also offers some backwards compatibility — many Z-Wave and ZigBee radio modules can be updated to work with the new protocol. While Thread doesn’t yet enjoy the huge uptake of Z-Wave, it’s likely to become much more widespread in future.
When choosing a home automation protocol, there are several considerations to keep in mind. Where low power is a priority, BLE is a good choice. If my priority was interoperability, I would favour Z-Wave because of its vast family of devices. For cloud connectivity and long-term development, I would prefer Thread‘s IPv6 capability.