Home Automation Protocols
What, exactly, can you do with home automation?
The most common project is to automate lights, thermostat settings, and irrigation, but you can also tie HA (Home Automation) into security systems using extra sensors, triggered lights, or other outputs. Your imagination and creativity may be your only limits. As for me, my budget was the determinant in how far I could go. Nevertheless, this is the story of a real-world home automation installation. Some of the options I had to bypass due to monetary constraints included thermostat control, voice interaction, irrigation, and home theater control.
Another factor (besides budget) in the planning process is picking a HA protocol on which to base a new system. There are four major players in HA, each with its own strengths and weaknesses.
X-10 has been around the longest, and is by far the least expensive. X-10 was originally designed to send its signals through existing power wiring, but was later adapted to transmit wirelessly as well. X-10 has a broad catalog of available devices, but its primary downfall is its lack of robustness. The problem is that the protocol is specified with one-way communication and includes no checks for commands making it through to the targeted device.
UPB was designed to counter X-10's weaknesses by utilizing a higher voltage and stronger signal. UPB is a powerline-only communication protocol, so some devices are much harder to install. In addition, a high cost for the technology has made UPB prohibitive to buy into, and has likely stunted the growth of the technology.
Z-wave is a newer protocol and is dependent on wireless signals at 908.42MHz (though that varies slightly depending on the country in which the device is intended for sale). Due to its wireless nature, it has become very popular for refitting older homes with home automation, and since it operates at ~900MHz there is no need to worry about wireless network interference. Some of the concerns of Z-wave are its proprietary technology, radio congestion with larger deployments, and low tolerance for failed, moved, or removed devices.
Insteon is another newer protocol, and it utilizes both powerline and 915MHz wireless signals for a robust network. Each device acts a transceiver in that it will receive a signal and transmit the signal again if it is not the addressed device. Insteon can also communicate via X-10 signals, an ability that has made it popular for those who have already invested in X-10 and want to update to a newer, more robust protocol.
One of Insteon's caveats is that most of the wired-in devices require the neutral wires to be in the switch boxes. This type of wiring is generally not found in older homes. Insteon also released some switches earlier on that had a high failure rate, although they did extend the warranty on those and have replaced the model with a better switch.
So, now it's time to choose which protocol to use. X10 is not really a valid option for me, as it is not being developed anymore and lacks feedback. UPB is a niche market for the wealthier crowd, many of whom don't know how else to spend their money, and that's definitely not me either. That only leaves Z-wave and Insteon as valid options. If I had to guess, I would say one of these, if not both, will be around for a long time to come. But right now they are both fighting for recognition and market share. For my installation, I chose Insteon due to cost, availability, control options, and robustness.