How Home Automation Really Work

Home automation has a tumultuous history. For many years, technological trends have come and gone, but one of the first companies to achieve success is still in operation.

Many smart home products got their start in 1975, when a Scottish company created X10. X10 allows compatible products to communicate with one another over a home’s existing electrical wires. All appliances and devices are receivers, while the system’s control mechanisms, such as remote controls or keypads, are transmitters. If you want to turn off a lamp in another room, the transmitter will send a message with the following numerical code:

• An indication to the system that it is about to issue a command,
• A unique unit number for the device responsible for receiving the command and
• A code that contains the command itself, such as “turn off.”

All of this is supposed to happen in under a second, but X10 has some limitations. Because the lines become “noisy” from powering other devices, communicating over them is not always reliable. Electronic interference can be interpreted as a command by an X10 device and acted upon, or it can be ignored entirely.

While X10 devices remain popular, new technologies have emerged to compete for your home networking dollars. Many new systems communicate through radio waves rather than power lines. BlueTooth, WiFi, and cell phone signals all work in this manner.

ZigBee and Z-Wave are two of the most well-known radio networks in home automation. Both of these technologies use mesh networks, which means that the message can be delivered in more than one way.

To determine the quickest route for messages, Z-Wave employs a Source Routing Algorithm. When a Z-Wave device is plugged into the system, the network controller recognizes the code, determines the device’s location, and adds it to the network. When a command is received, the controller employs the algorithm to determine how the message should be delivered. Because this routing can consume a lot of memory on a network, Z-Wave has created a device hierarchy: Some controllers start messages, while others are “slaves,” meaning they can only carry and respond to messages.

The name ZigBee exemplifies the mesh networking concept because messages from the transmitter zigzag like bees in search of the best path to the receiver. While Z-Wave uses proprietary technology to operate its system, ZigBee’s platform is based on the wireless personal network standard established by the Institute of Electrical and Electronics Engineers (IEEE). This means that any company can create a ZigBee-compatible product without paying licensing fees for the technology, which could give ZigBee a competitive advantage in the market. ZigBee, like Z-Wave, has fully functional devices (those that route messages) and reduced function devices (those that do not).

A wireless network allows for greater device placement flexibility, but, like electrical lines, it may experience interference. Some systems allow your home network to communicate via electrical wires as well as radio waves, resulting in a dual-mesh network. If the message is not received on one platform, it will try another. Rather than routing the message, the device in these new systems will broadcast it, and all devices will pick up and broadcast it until the command is executed. The devices function as peers, rather than one acting as an instigator and the other as a receptor. This means that the stronger the message, the more Insteon devices that are installed on a network.