Meanwhile homee has to offer three different cubes which can make your home smarter, more comfortable or more beautiful. If done right - everything at once! Solely the brain cube knows some tricks already and he never stops learning. We are working tirelessly to integrate as many new smart gadgets as possible therefore the number of supported technologies and devices is increasing with almost every update. For homeowners and smart home beginners this can quickly become overwhelming. To proactively prevent wrong decisions or purchases, which will be mourned afterwards I will introduce you with this little series of articles to our cubes, their wireless technology and their perfect area of use. I will try not to dive very deep into technical details and only mention the most important things. So don't be scared, this series is for everyone! Let's start right away with our little turquoise friend, the EnOcean cube!
EnOcean is the name of a wireless radio technology which was invented and patented in 2001 by a spinoff company of Siemens. Since 2008 the technology is maintained and further developed by the EnOcean alliance. The idea behind this technology is that sending small, short radio frames only needs so few energy, that it is possible to gather it from the environment around. The actual physical press of a button, for example, can be utilized to produce enough energy for for sending a radio frame using the piezoelectric effect. Same goes for sending a small frame which carries the current room temperature or humidity. For such purposes light is often used as the power source of choice using small solar panels. And that's the big deal with EnOcean, many devices are nearly completely free of maintenance work! That means no painful change of batteries, which are anyways always empty in the moment when it's least suitable.
But like always: where's light there is shadow! And that's the same thing with the short, small radio frames of usually simple-constructed EnOcean devices. Since there is only a very limited amount of power available to these devices, they can't do a lot or very complex things. For such kind of gadgets this mostly concerns channel access mechanisms, frame acknowledgement and encryption.
What does this mean to me?
- most EnOcean devices send their data either unencrypted or with a very simple kind of encryption
- for almost all EnOcean devices there is no way to make sure that your command really reached the device
- most EnOcean devices are unidirectional, that means they are either receivers (actuators) or transmitters (sensors) only
That surely doesn't mean that all EnOcean devices do have these disadvantages. There are solutions which are constantly connected to a power source or have a battery (which actually negates the big advantage that EnOcean has). Such kind of devices are capable of different styles of bidirectional communication. You can also find gadgets that confirm received frames or that send and receive encrypted signals. But here is the catch!
For almost everything there are different ways to solve the problem. There are different kinds of bidirectional communication, different approaches to encryption and a generally large room for producers to adapt the standard to their needs. For example, there is no single truth when it comes to bidirectional communication, more like 3-4 truths. This somehow creates substandards - if you like to call them that way - within EnOcean. I assume you can imagine what this means for gateways like homee.
This all doesn't sound actually smart, right? So how do these devices then fit into the big picture of a smart home? Well, don't judge too fast here! This technology has, like every technology, its benefits and its drawbacks. But with the knowledge of these things you can find niches and tasks which build on the benefits and avoid the drawbacks!
So, where to use EnOcean?
- Do you want to know how warm it's in your living room? - EnOcean
- Do you want to know if all doors and windows are closed? - EnOcean
- Do you want to know if there is someone at home? - EnOcean
Long story short: EnOcean fits very well for all kind of measuring tasks. This is an area where 100% reliable data transmission is not always necessary (well, door and window sensors do make an exception here of course). Loosing a single temperature or humidity measurement doesn't affect the general reliability of the whole system, since nearly all these environmental measurements are inert and do not change suddenly.
And where should I look for something different?
Even though I mentioned that the are technical solutions for bidirectional communication with EnOcean, I would recommend using something different when it comes to switching, dimming, moving or any other kind of manipulating things around you. homee offers two other solutions for such tasks which will be discussed in later parts of this series. This is simply because these other technologies have direct feedback about the success or failure of your command sent to the device. This is a huge deal if you want to control your home from somewhere else meaning you are not at home to see if your command really worked. This builds the trust that everything is working well. Did the light really turn off? Did the blinds really close? Without radio feedback you will never really know! There are many EnOcean actuators which were developed with a mindset completely different from that of a central controlling unit, which hears everything and sends all commands. They were often intended to be paired directly to each other and are therefore made for this kind of use case. Using such devices with a central controlling unit like homee requires all kinds of somewhat „hacky“ workarounds, which is of course error prune and elaborate. For example, in order to use different switching actuators, which are often used in off-the-shelf homes, we would need to send frames looking like that from a simple button, convincing the device to believe that homee is a button and it was just pressed. These hacks exist and they do work, but they have technical limitations which make them a pain in the ass to use and, at the end, have a negative impact on user experience.
What about range?
As mentioned in the beginning, EnOcean uses very simple radio frames in order to be as energy-efficient as possible. This is also the reason why there is no advanced mechanism for relaying frames from one device to another. Such kind of algorithms would eat up a lot of energy which was a no-go during the development of EnOcean. That being said, there is still a way to increase wireless range of a EnOcean network. Some devices can be configured to simply repeat all frames they receive, this is called repeating. With clever use of this technique it's possible to cover even moderately-sized homes easily. But when it comes to repeating, the slogan should be: less is more! Use repeaters moderately and only where they are really needed. Just stuffing your whole home with repeaters will have the opposite effect, since constant repeating of each frame would cause the network to be needlessly flooded all the time. But targeted use of repeaters is a good way to increase the coverage of your network.
With this simple advises it will hopefully become easier for you to find a suitable use case for our turquoise friend and its devices.
Next time I will have look at our Z-Wave cube with hope to give you some smart tips for the purple cube.