The importance of pushbuttons in KNX. "Talking Smart Homes with: Daniel Leitzbach"

In our third episode of Talking Smart Homes, we are discussing the importance of pushbuttons in smart homes with Daniel Leitzbach of Cojacon.

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Episode transcript

Hey everybody! I'm Satja and this is the third episode of Talking Smart Homes. Our guest today is Daniel Leitzbach, the CEO of Munich-based smart home company COJACON. Hi Daniel!

Hi Satja, thanks for inviting me to Talking Smart Homes.

Yeah, thanks for being here, and today's topic is push buttons, or more generally manual control in KNX because I feel like this is an important topic because, if you ask most people about user interfaces in KNX, they will they will think like, app for a smart home or maybe even voice control. But in reality most of the controls or most of the commands are still done through manual controls like manual push buttons, and this is why the configuration and the positioning of manual controls is a crucial factor if we're talking about the usability and user friendliness of the KNX smart home. But before we start: Daniel, maybe you can tell us something about yourself and the COJACON company?

Of course, yeah, so as you told already, my name is Daniel um I'm a passionate smart home engineer and i'm with COJACON since four years now since it was founded. COJACON is a typical smart home integrator or more or less smart home designer so we do private houses, KNX and all the smart home systems here you have on the market, and furthermore we are also technology consultants for construction industry in terms of smart building and digitalization.

Okay, so we have a big professional here! So let's go to the push buttons. So first question: probably you've encountered, you know, in your career you've encountered a customer that would say like: "I want to do a smart home without any push buttons on the wall." So do you think this is doable? And furthermore, do you think this is wise to do, and can you actually make a smart home without any manual controls on the walls?

Well, I have a customer who did that. So he is controlling everything with Alexa. I would definitely say that's doable, you have quite a lot of solutions on the market, and you can combine KNX very nicely with Alexa, Siri, and also Google Assistant. I wouldn't say it's wise, you know, the fact is, a smart home, the basic principle still needs to be usability. So you mentioned it in your intro, you need to have an intuitive user interface and talking to something you can see is not really intuitive for everyone, like your guests, your children, your grandma, and I think that's a big issue you have. So for us, speech or voice control is more or less an add-on to the basic control principles of your smart home.

Okay, so basically it depends on the user, but generally it's not recommended to do it in the whole house. But what about, you know, are there some cases when this works? Like maybe a hallway, garage, basement... if you have uh presence sensors or a movement detection sensor, do you still need a switch on the wall?

Well speaking for the voice control I would say um you can do this for the whole house of course. Again, um you need to do this as an add-on, you need to do this additionally. For example, a big use case is when you're in the living room. So i'm speaking to your assistant from your living room, from your couch, for example turning off lights, closing shutters. It's very user friendly, and very very fancy and cool. Speaking of sensors like the presence sensors, I definitely recommend to use them for rooms like basements, technical rooms, or like hallways or rooms without windows, for example where you always have to switch on the light and switch it off. So a basic principle for a smart home design from our perspective is that you automate things that you don't want to control manually. So again, speaking of some technical room or like garage for example, you always need light you don't have windows, so you always have to switch on and switch off, and you just pass through this room so you can easily automate it. That's not the case for every kind of room, but as you mentioned, hallways for example, for this kind of room it's very useful. So you can choose presence detector instead of typical control here so instead of presence sensors AND a switch, just a presence sensor. So this depends on the customer. We also have, for example, for big apartment buildings we often use this additionally to a switch also in the hallway, because sometimes you have customers that are not comfortable with with presence detection, so they want to switch the presence detection off and then you don't have a control of the light in the hallway. There are also products on the market where you have a switch and the presence detection in one sensor, in the same device, and that's a good solution for this kind of customer.

Okay, thanks Daniel. Now let's take a look at the different types of push buttons that are available on the market. I mean, there is a wide variety of different shapes, sizes, and colors but basically you can divide all of those push buttons into two types: the classical push buttons, like the ones that you use when you're doing a home without any smart home system, and then you have the KNX push buttons. What would you say are the main differences between those two types in terms of usability?

Yeah well there's really one big difference between classic switches and digital switches. So you need to mention, although it's KNX for example, it's a digital switch. It can still look like a classic switch, the difference is, those digital switches, they can provide feedback, so they're a bidirectional user interface. That's something a classical switch cannot do. So our best example for this is if you compare a traditional switch which remains into position when you switch a light on for example, this cannot be moved from something else, you know, it stays in position, so it cannot provide feedback. If someone or something from another system is controlling the light, turning it off for example, the switch will always stay in this position. So when combining traditional switches with a smart home, you always use rocker switches, sometimes two-way rocker switches, and that works quite good. But the feedback is also something you shouldn't neglect so in terms of usability you can have LEDs, you have for example temperature indication, and then you have more usability out of this one switch.

Okay, I get it. But a lot of customers will of course consider these classical switches because if you look just at the price of the the switch or rocker switch as you say, and the price of the typical KNX push button, of course, the first one is more affordable. But in case you decide for the classical rocker switches, for example, then you also need additional KNX equipment like, the binary input modules, and the temperature sensors, which are normally already included in the KNX push buttons. Would you say, that the customer is right in assuming that he will get the same functionality for less money if he chooses the classical switches?

Well, so, in terms of automation in terms of complete smart home solution I would say you can still get the same functionality from your automation at all. So most of the time when we have, for example, apartments where we combine those classic switches with server-based systems, so you have binary inputs on the server maybe you also have, you know, the products it's KNX actors combined with binary inputs something used very often in hotels. With these types of products or even with servers you can still implement everything on those actors and on those service, but the difference is: you won't get the same usability on the interface, that's what's happening in the room, that's what you don't see. So then all the functions will transfer into applications, and into automation that's not really seen. So direct feedback is missing of course.

And of course, if you use the binary inputs which are in the electrical fuse box then probably you use more cable as well right?

Well, you use more cable and it's getting more complex. For example: if you have a classic switch but it's KNX based, you just have the KNX cable. You plug it in and that's it. If you have a normal power cable, and then the binary input, and then you have those small wires going into the rocker switch, and you know, that's something when the electrician will say to you: "You know what, the wall box is very small I cannot get all of this in." So it's not too easy. So sometimes we use binary inputs or switches with binary inputs, and then we don't use classic power cables, but some communication cables, and just use the binary inputs on them.

Okay I get it. Okay, from the top of your head, you know, what money should be spent on push buttons, on KNX push buttons, in a typical family house? Like 200 square meters?

Well, as talking in the prior questions I would say this depends on the concept of the control, and the user interfaces, and the switches. So talking about those classic switches with binary inputs maybe in a 200 square meter house you could maybe get it for I would say 1 500 euros or 1 000, because of course you have to have the intelligent components in your electric box or behind the switch, so this also raises your cost. Speaking of traditional KNX devices or more fancy KNX devices, I would say you need to estimate for example one switch per 10 square meters. You have some rooms that have more switches, like a kitchen, or you have rooms with less switches, like just a toilet. And then speaking about price I would say it's something in between 100 and 200 euros to have a good usability. So let's say the range is 1500 to around 3000 maybe.

Okay, that's an interesting train of thought. But if you would go for, like, upper limit, it doesn't exist right?

Well, as always, upper limit doesn't exist. You can go by far more fancy as well and then there's no upper limit.

Let's talk about the configuration of push buttons or, you know, the push button panels, because most of us are used to that, and it's like how it's been done in the past: you always have one button per one device, so like, one light one push button, one shade one push button... But in the modern living room you can have like, up to ten lighting bodies, and you can have like three to five or even more shades, and in that case you will get like 15 push buttons on the wall, which I believe is very user unfriendly, and defies the basic concept of  smart home which is: easy and understandable control. How would you say the push buttons configuration should be done in a modern KNX smart home?

Yeah, so what you're talking about, is really a big problem. Most of the smart homes are still integrated by the typical electricians, and that's what they are used to as well, and that's what also most of the customers are used to: to have one switch per one function. That's something we really want to interrupt here. We need to break this principle, and what typically system integrators do is providing a scene-based control concept. So the idea is to combine, in an intelligent way in a smart way, typical lighting or function situations in your room. Because when you imagine yourself, how you're living in your house or in your apartment, you're typically living in scenes, you're not living in functions. You're going to your couch for example watching TV and when you move in your apartment you need a few weeks, but then you have your typical setup for watching TV: it's maybe one light is dimmed to 30 percent and you close the shutters by 75 percent and that's your mood or your scene for watching TV. And that's what you should integrate in the control concept as well. So what we do most of the time is; we remain one basic switch on the typical heat, on the typical insulation heat, we remain one switch, and it's a two-fold rocker switch. And what it does, when you enter the room, and you push it, it activates the scene "room entrance". And this is for example, basic lighting setup, and when you switch it off or when you go from the room, then it activates the scene "close room" for example, it's however you want to name it, but what's the idea behind it is that it's still intuitive for everyone of your guests, for children, whoever wants to have light for example, because speaking of light, this is something that's really important; light has to function immediately, you need to know where the light is, and that's what we integrate with this kind of scene, and with the scene "close room". You can also combine this for example, with your speakers, and it stops your radio, and that's something we really try to integrate in every room. And then additionally on top, we have typical lighting or typical living scenes like TV ambience, cooking, eating... and that's something we integrate on top of, maybe on other switches, or maybe on the same ones.

So basically we can reduce the number of push buttons and improve the functionality by adding scenes to the push buttons right? So you've already mentioned some scenes, but I would say, like the most common scene I can think of is like the "away" scene. So you leave, nobody is home, so you want all the shades to close, and all the lights to turn off, and maybe the alarm system to activate itself. What are the other interesting or usable scenes that you use in your day-to-day work, and where should they be located in the house?

Yeah that's a really good point. So you mentioned already those scenes which are called central scenes for us. So in the hallway next to your entrance door, most of the time, we place a room controller or switch which provides more functionality, and there you have these "away" scenes you were mentioning already. You also have a "coming home" scene for example, because we often also integrate the heating system, so when you leave your home, the heating system is lowered by two degrees for example which directly saves you some money, and when you come back home the heating system goes back to comfort. So that's something you also should take into account. Another very special scene is going into holiday. So a lot of systems provide some simulation, you know, which imitates your behavior.

Like a presence simulation?

Yeah, it's like a presence simulation, so that's something we also integrate very often. And then going away from the central scenes there's also something happening in the bedroom, master bedroom for example, so, "good night", "good morning" is also something we really use very often, because this is the same situation; you maybe forgot some light somewhere, and you go into bed, and you're really tired, and then you just press one switch, and all lights shut. And you can also integrate this in two ways; most of the KNX devices provide a short press, and a long press, so what we often do is, the short press is just for lighting, and long press is for other functionalities like shutters for example. Then they close as well.

Oh, that's a nice concept, I haven't thought of that before! But, if you look at the typical electrical design project for a house or apartment, the push buttons are almost always done in a way that we discussed before; so one push button one device, and no scene buttons at all. So who is actually responsible, and who should actually tell the customer, you know, present him with this different concept of push buttons with a lot of scene push buttons included like you described before? So is it the smart home integrator, is it electrician, smart home designer, electrical designer, architect maybe? I don't know...

So I would say... it's a good question that you're asking me, because there's of course a reason companies like Cojacon came up several years ago, and we're not the only ones doing this kind of work, because in the construction industry right now there's one significant gap. It's the same like Jorge mentioned in episode one. There's a need for some kind of smart home designer. That's what system integrators provide more or less, but some of the system integrators are more I.T. specialists, and some of them - like us - we try to do that more on the architectural side of thinking about smart homes. So from our perspective we are the connection between the customer, the architect, and the electrician. We try to think about the living situations in your home like an architect, so we do a lot of consulting of the customer, we try to think how he will be living, we try to anticipate all the situations he has, and on the other hand we need to be technically speaking like the electrician, so that's a completely different language, and so we see today that in a lot of projects this kind of connecting expert is missing. When i'm speaking like a customer i'm thinking as a customer you really need to force your electrician to think in a design manner and that's something most of the time they don't do. So I would say, definitely try to integrate some company like a smart home designer into your construction.

Because basically you do a little bit more work before with all this consulting, but then in the end you have a good product. And also if the push buttons are not set right then you have to return to to the project many times and you know, reiterate the functionality, and in the end you do the same amount of work but you have worse results.

Like, yes, that's also a big problem for the smart home industry because what I am often faced with is this opinion like "Okay smart home doesn't really work". We have a lot of requests from customers who got a smart home provided by an electrician company for example, that is not working really good, so they asked us to join it, to see if we can change the programming, and what really needs to happen is: the customers need to change their mind a little bit. So when you have I.T. infrastructure for example, you will always have some service contract with your I.T. expert, with the company, and that's something that will happen in smart home industry as well. So the smart home company or the smart home designer will be the first point of contact in case something's not working correctly, because they can provide better additional service. The electrician is often coming to your house, checking something, but the system integrator as he is more or less I.T. based he can check everything remotely for example. So that's a big problem, and we need to change the mind in the industry, and integrate this new expert in the construction site.

Yeah, okay, thanks for this answer. What about more advanced manual control devices like room controllers or even touch screens? A lot of people imagine a smart home is, you know, a touchscreen on the wall, and you also see it in many smart home showrooms. So do you think a touchscreen on the wall is a good idea or not?

Uh, definitely not in every room. I have for example customers who want to have an iPad in every room, but I wouldn't say that's a good idea. Tablets are more or less often IP based, so there's some kind of software, and software is not so reliable like typical building automation mechanics for example. So I would say you should have a basic control setup, like basic switches or room controllers which are also basic KNX switches, and maybe on the central place in the apartment or in your house you can have iPads or tablets. So there are also tablets provided by the big switch companies and then you can use these for graphic visualizations, for having the video intercom, for controlling some automations, for example, on your server. That's something where you use the tablet, but not for basic switching operations, because you have to unlock it for example, it goes into deep sleep and that's not a best idea.

Okay. If we're talking about the functionality of push buttons; you mentioned some other functions before besides lights and shades. Which functions do you think are cool to have tied to the push buttons?

Well, typically, or what most of the customers ask for is volume control for their audio system. So that's something they really like to use on the switch as well. What I like to integrate for example is controlling some kind of automations, because what we didn't talk about, in terms of controllability of your smart home, is: you need  to take care of the control controllability for the customer. So the worst thing that can happen is that the customer gets the feeling he's not able to control their house anymore. And that's something that happens quite often when you provide fancy automations directly integrated into the KNX system. So for example: in terms of lighting you can provide human-centric light, adaptive lighting that changes the color by day. And sometimes the customer asks himself "Okay, now why is the color of my light orange?" So what I want to integrate or what I like to integrate is feedback, and the switch for this kind of automation, so that he can see "Okay there's a simulation running and I can stop this simulation directly on the switch."

Yeah, probably also in the case of weather station and smart smart shading control, like also that automation could be on the switch right? To turn it on?

Yes, smart smart shading is another very good example that's also very difficult if you automate it, because most of the time it's wrong. So a customer is asking himself "Why is my sunshade going up or going down?" So a good idea for this example is to provide the room automation signal of presence, so if there's presence in the room you just pause the automation, and if the presence is gone then you continue.

Nice, okay! So let's do some quick questions: What do you prefer - labeled engraved push buttons, or not?

Well, definitely not labeled! That's the worst I could imagine. I like engraved switches sometimes in terms of design, but I'm more of a fan of some kind of adaptive switches with maybe a small display so yeah, that's my choice.

Okay. Can you name your three favorite brands and models of KNX push buttons?

I would say my favorite model is the basalte Sentido. I really love the multi-touch control. You can still have the basic principle of room on and off, but you have more functionality. I also do like the basic KNX switches from Gira as they provide a classic design, so you can integrate them as well for example in old systems with the multi switch optics. In terms of room controllers, I also like the Gira Taste Sensor 4, very sleek design, but for display switches for example, I like the Merten Multi-Touch Pro. It's really sleek, it's just a black small rectangular switch and it has a lot of functionality.

Yeah, I like that one as well. What about touchscreens, do you have a favorite here as well?

We use quite often the gira G1 as it connects quite good to the video intercom, but I would say we're still experimenting with different products on the market. I'm not feeling too good with the Gira one, so we have PEAKnx for example here right now, and experimenting with this one. It's very interesting, it's based on Windows 10 IoT. But yeah, that's the two I would suggest right now.

Okay thanks. And what in your view are the most common mistakes or bad practices when selecting push buttons?

Well, i'd say the worst is to just rely on what your electrician is selling you, because you need to know the sales principle, especially in Germany, is like, the companies have a contract with the electrician company to get specific discounts. So most of the time, the decision of the electrician company is not based on functionality of the switch. So there could be even a switch that fits into your frame design for example if you want to have a specific frame design, there could be a switch that fits into this frame, but it's from the different company, but providing more information or more functionality. So I would definitely say, keep your eyes open, do some research on the market, just Google your frame design and KNX and let's see what's coming up on Google. That, I would say, is the worst mistake you can do.

Do you have any advice for the integrators? What should they be mindful of when proposing, installing, and programming the push buttons?

So for the installers or for my colleagues I'm always saying: you need to keep in mind that everyone who's living in this house needs to understand what this switch is doing. The worst is when you press the switch and you don't understand what it's doing. For example, sometimes you see switches, they are integrated in a way that they change something or they provide on and off signal, so when you have switched the light already on and then you press the button and it sends an on signal nothing happens. In this case there are some customers, they are directly dialing you, and say "Okay something is wrong, it doesn't work!" So keep in mind what situations can come up when controlling something with this switch, and this should be really foolproof.

Okay! That's it, I'm actually all out of questions. So do you have anything to add for the end?

Well I think usability is really a big topic, so for all of the customers, and for all of the integrators: keep that in mind, because as soon as when you're living in your house, and have the feeling of losing control that's something you don't want to have. So everyone should keep that in mind, and then you get intuitive and really smart homes.

So, another episode done! Daniel thank you for sharing your wisdom!

Thanks for having me Satja.

And for the viewers: there will be another survey on the topic of push buttons! Check it out when it's available, and like always; like, subscribe, follow us, share, and comment, and most importantly, join us for the next episode of Talking Smart Homes. Same 1Home time, same 1Home channel. Live long and prosper!