There are two basic problems. 1) getting the devices to find each other and communicate in some reasonably secure way, and 2) controlling them in some user-friendly manner.
1) is still a mess. Things that are hooked to line power ought to talk over the power line. There are lots of standards for that, from the old X10 (1980s, low bandwidth, poor noise immunity, no security), bidirectional X10, Echelon (1990s, low bandwidth, very good noise immunity, some security), HomePlug (2000s, high bandwidth, some security), plus some proprietary systems. X10 refuses to die, and HomePlug's bandwidth is overkill for lighting. Echelon mostly gave up on the home and went on to become the standard for subway and rail automation (signs, lighting, HVAC, doors, etc.) because of the good noise immunity. They're working on a new approach to lighting, where LED lights run on 48VDC. This is a bit radical for home automation.
If you have any of these, it's useful to have a whole-house RF filter where power enters the house or apartment to isolate your network segment from everybody else on the same pole transformer. These are cheap ($6 or so) but have to be installed by an electrician. This is a big obstacle to power line networking.
Then there are the RF-based networks. WiFi, Zigbee, etc. These have range limitations and may not work through walls. Despite all the headaches of RF networking, most of the IoT vendors are going that way because they get to dump the range problem on the user.
>If you have any of these, it's useful to have a whole-house RF filter where power enters the house or apartment to isolate your network segment from everybody else on the same pole transformer.
I considered X10 a few years back, and when this issue came up I scrapped that idea.
I think it would work better if these controllers used out of band communication, but that would require running an extra set of wires.
1) is still a mess. Things that are hooked to line power ought to talk over the power line. There are lots of standards for that, from the old X10 (1980s, low bandwidth, poor noise immunity, no security), bidirectional X10, Echelon (1990s, low bandwidth, very good noise immunity, some security), HomePlug (2000s, high bandwidth, some security), plus some proprietary systems. X10 refuses to die, and HomePlug's bandwidth is overkill for lighting. Echelon mostly gave up on the home and went on to become the standard for subway and rail automation (signs, lighting, HVAC, doors, etc.) because of the good noise immunity. They're working on a new approach to lighting, where LED lights run on 48VDC. This is a bit radical for home automation.
If you have any of these, it's useful to have a whole-house RF filter where power enters the house or apartment to isolate your network segment from everybody else on the same pole transformer. These are cheap ($6 or so) but have to be installed by an electrician. This is a big obstacle to power line networking.
Then there are the RF-based networks. WiFi, Zigbee, etc. These have range limitations and may not work through walls. Despite all the headaches of RF networking, most of the IoT vendors are going that way because they get to dump the range problem on the user.