Tag Archives: raspberry pi

Choosing a z-wave controller

In the last post, I looked at solutions for starting out my automated home and decided to go with z-wave as the primary protocol to start investing in. Now, we need to start with the central point, the primary controller which is going to act as the central hub for the network.

The first thing that I needed was a controller. There are quite a few options for this, including off-the-shelf options from companies like Fibaro and SmartThings as well as applications which can be installed on a home server. My initial concern was this is a fairly new market that isn’t very big yet and I didn’t know which of the companies were going to last and keep supporting the hardware that they had made. There was of course the cost aspect with the majority of off-the-shelf solutions costing over £100.

Like the SmartThings hub, both OpenHAB and Domoticz offer support for protocols other than zwave, including Phillips Hue, Nest, MQTT, IFTTT and Twitter. So they can integrate with other solutions that might be useful.

Being happy to manage a small Linux server, I decided that I wanted to run a software based controller rather than an off-the-shelf box as it could then be customised to do more if I want it to in the future. It also makes it potentially easier to switch software at a later date too. The key players in the home automation software space seem to be Domoticz and OpenHab. They both look decent and seem to have good support, though OpenHab offers an official iOS app while Domoticz seems to leave this to third parties. OpenHab also seems to have a very responsive forum with the developers quickly responding to people’s issues which settled it as the winner.

With the application chosen, I needed somewhere to run it. Although the household computer is usually running, “usually” isn’t going to cut it if it’s a critical part of the house’s lights and heating. The Raspberry Pi is cheap enough and has a desirably low energy footprint to be running constantly so it seemed the perfect choice. Out of the box though, the Raspberry Pi can’t control zwave devices as it lacks the necessary hardware. This is easy enough to solve, with several manufacturers making USB radios (that would also be compatible with any other machine with a USB port) and the Razberry daughterboard which is dedicated to the Pi. In choosing a hardware radio, definitely consult the documentation of the application chosen to make sure there are no compatibility issues though.

Together, the Pi and the Razberry came to nearly £100 – not much cheaper than the dedicated boxes – but the Pi can at least be re-purposed if it turns out not to be the best solution, and is flexible in that it can run other things too.

Getting started with Home Automation

In the home automation space, I first started looking at the central heating controls as that seems the place with the most to gain. Too often our heating is on when we’ve gone out—or off because we would ordinarily be out at that time—what if the heating knew when we were home and I didn’t have to worry about fiddling with the heating schedules?

After getting lost in the various central heating and hot water control products though, I realised that it would inevitably go further than that – it would be great to control lights, alarms and just about everything else. So, I started looking for something (or a suite of things) that would integrate and talk to each other.

Protocol

LightWave RF

This is the stuff you might find on display in your local B&Q. I originally started looking into LightWave as James has some experience with it, and on the whole it sounds like an almost perfect solution for controlling lights–

  • their hardware is really good looking and fairly inexpensive
  • the switches just replace a standard UK switch plate
  • there are things like the additional stick-on battery switches so that switches can be added without drilling, cutting or wiring
  • there are lots of add-ons available such as ambient light sensors and motion sensors.

However–

  • LightWave just doesn’t play all that well with other technologies. There is software available that can talk to LightWave but James had some major issues with latency that are a bit of a deal breaker.
  • The motion and contact sensors seemingly can only be used to turn on lights, so can’t be used as an alarm system by sending a notification to my phone.
  • The switches don’t have the concept of a “state”. So they can be switched remotely, but you are blind as to their current status unless you can see the actual light. That’s no good then for checking that lights haven’t been left on while I’m at work.

On the whole, the concept is ideal. The idea of replacing just a small number of switches is far more appealing than a concept like Hue which involves replacing every light bulb at something like £40 each. I counted, and with various lamps our living room has 9 light bulbs alone. More importantly all of the technologies have to be transparent to those who don’t know about them. For example, our parents are often over to help out with child care, and they wouldn’t be too impressed if they needed an app to switch on the light.

Zigbee

Zigbee is one of the IoT protocols, and is used in products like the Phillips Hue. When researching though, there doesn’t seem to be a market of products that can interact. Rather, it seems like companies like Phillips are using it in a proprietary fashion.

Z-wave

One of the emerging standard seems to be z-wave. Z-wave is a protocol that supports most uses – including lights, sensors, alarms and just about anything else. The light switches don’t seem to be there yet, as most of them are awful looking white plastic things unless money isn’t an option. There aren’t any power socket faceplates, just the plug-ins that are roughly analogous to the timer switches we’re all used to. But it does everything else, and surely the market will catch up and make these missing products (or start to compete on price!).

Conclusion

So, after some deliberation I’m going to start out slow and try out z-wave as the backbone of my automated home. It seems that there are some good, affordable products out there using z-wave and conceptually they work as I want them to.