Smart home – how can you control sockets and lighting remotely?

Hello,
I’d like to offer my sincere congratulations to Romek and express my admiration for his hard work and… determination. His approach is absolutely the right one and very modern – and he stands a good chance of creating his own BMS system (distributed control in junction boxes, etc.). However, the biggest problem I see with this ‘pure DIY’ approach is the sheer amount of work required to ensure such a solution can manage the home efficiently. In practice, there are so many technical issues to resolve when connecting such a BMS to boilers, solar panels and ventilation systems that I honestly admire anyone who’s willing to build it from scratch. It’s a bit like wanting to go off-roading and starting by building an off-road vehicle – rather than perfecting your 4WD driving technique;-) I suppose, after many attempts, it might be possible to build a car better than the off-road vehicles generally available, but would we have enough time in our lives to get our fill of driving it? I don’t know.
In my opinion, with BMS, you need to take good, tried-and-tested technology and have fun applying it to new tasks, rather than creating new technologies… But that’s just my personal view, of course. The sheer number of variables and protocols involved in a BMS like this is daunting even for me – and I do know a thing or two about it. Let’s say we want to know who’s at home – OK, a simple presence detection system can be built yourself, just like Romek did. But the more you do, the more you want to do, and soon we’ll want to know how much heat we’re using (or we’ll want to optimise that usage). Of course, you could just use a heat meter and be content with it sending a pulse every 100 KJ. But perhaps we’d like to know a bit more about how to heat the house most efficiently, keep it at a certain temperature, and why it’s sometimes cold inside. For that, a standard heat meter with a pulse output won’t be enough... Of course, you could write the software from scratch, but that’s another huge job… Or, using standard technology (such as LONWORKS, which I use), we could order a heat meter with such an output – and immediately have all the parameters (inlet and outlet temperatures, instantaneous power, heat supplied over a given period, etc.) readily available. Or perhaps we already have a heat meter using a different technology – MBUS – no problem, we order an MBUS-Lon interface and it works a treat straight away. We order blind controllers – either we wire everything up ourselves or we order a controller with a LON output. If we want to control a pump – we’ll get one with LON control or 0–10 VDC; either way, we’ve got it sorted and tested on LON straight away… it’s just a matter of ordering the right components… There are countless examples like this, and as a result, I wouldn’t entrust the control of heating or DHW to a system based on RS-485 and Windows (perhaps Vista?). Nevertheless, I sincerely admire people who are willing to take on such a huge task themselves – I take my hat off to them and send my warmest regards.
Jacek Unihome

Hi Mischa.

As soon as I’m back from my holiday after the 14th, I’ll write to you to explain how to sort this out using, for example, a SATEL INTEGRA series control panel. What you want to do at your place is something I’ve had set up for a long time now, both in my offices and in a fairly large house (340 m), and it works flawlessly (I’m renovating the house, so I can always add something if you have an idea). I’ve set up the system as a distributed installation, meaning I have four main nodes, each fitted with INT-ORS expanders and CA-64 EPS + E units (in some cases). Each circuit is routed to one of the nodes to minimise the length of the supply lines. Each node is powered by a separate 5x4mm cable from the main distribution board in the basement. All nodes are fitted with a 17 Ah battery and 12/230 V inverters, as part of the system powers LED lighting (230 V), which also serves as emergency lighting in the event of a power cut. I can control virtually all circuits, including remote control via a GSM4 module and an Ethernet module. The only problem was finding nice push-button switches, as I couldn’t find any – or rather, my wife didn’t like them (they have to be normally open and have a return spring) – so I made them myself by inserting a suitable spring into a standard switch. As well as the switches, the control system receives signals from various sensors: twilight, rain, motion, reed switches, and 4-channel radio systems, Using distributed nodes reduces your costs because, as others have mentioned, you don’t need to build a relay cabinet; instead, you can create several smaller panels, which in practice will also allow you to fit in standard safety and surge protection devices responsible for, for example, a specific floor (I have the main panel installed in the basement, and that’s where the first surge protectors are fitted). The result of planning the installation in this way is that, in the event of a short circuit, you don’t have to rush down to the basement ‘because the whole building has gone out’ but instead go to the distribution box on the floor; the ‘affected floor’ is lit by an LED emergency power supply. As well as being convenient, this helps balance the load across the individual phases of the power supply. Of course, these are just some of the many aspects of having a smart installation I don’t have time to write about the rest as I’m off on holiday. I realise that, for example, the control of temperature valves operates on a NO/NC basis rather than continuously, but the room temperature switch works in exactly the same way (once the set temperature is reached, the relay ‘clicks’ and no heat is supplied). And the key factor is the cost of such a solution compared to the prices of so-called ‘off-the-shelf’ units from manufacturers.

Hello everyone!

I’d like to discuss the topic of a ‘smart’ home installation. I’m thinking of setting something like this up, as I’ll be building a house soon. For now, this is how I envisage it:

1. Cables. An RS485 bus – Category 5 UTP/FTP twisted-pair cable. Run throughout the house with access points in the light switches, the server room and I’m not sure where else – perhaps in a few sockets, and maybe something else will occur to me. Plus a power cable for the control devices – I don’t know what sort of cable yet, but obviously it’ll be a single pair. This cable or cables do not necessarily have to follow the same topology as the bus; rather, they should be arranged in as star-shaped a configuration as possible, to avoid distant points with significant voltage drops.

2. Assumption – the possibility of gradual expansion. To start with, just the cabling, and in the junction boxes, standard light switches, standard sockets, etc.

Once I’ve got that sorted, I can play around further, so:

3. Communication via the RS485 standard. Protocol – well, that’s where things start to get tricky for me. So far, I can see two options. Let’s consider an example.

I want a button in the hall to switch off all the lights in the house. Perhaps this will be the light switch in the vestibule, which, when pressed quickly three or four times in a row, will switch off all the lights in the house.

3a. Distributed version. To achieve this, I would fit a microcontroller into this ‘magic’ switch (as well as into all the others), connected to my RS485 bus, which, upon detecting the ‘secret’ combination, would send ‘turn off the lights’ commands to the other switches. As you can see, this is a distributed version of the entire system, i.e. without centralised control. If one of the switches breaks, I can temporarily replace it with a traditional one. If the bus goes haywire, all the lights will carry on working as normal; I’ll lose the ability to issue ‘remote’ commands and lose monitoring, but the house will still ‘work’. I can add further monitoring and/or control components to the system. On April Fools’ Day, I could swap the functions of the switches so that the living room light switch turns on the kitchen light, and so on. To implement such a version, a protocol allowing for multiple masters would be required. I suppose I’d have to design something of my own, perhaps based on the token ring principle (token passing).

3b. Centralised version. MODBUS is a popular protocol. The problem is that MODBUS assumes there will be one master, with the rest being slaves. One could envisage the same scenario with centralised control. The master – a computer, or some other ‘central’ unit with a microcontroller – repeatedly sends queries to all the slaves, asking if they wish to transmit anything. If so, the master asks what the slave would like to transmit, and once it receives this information, the master decides what to do with it next. In such a system, the logic behind the whole operation is effectively contained within the master node. It is there that the decision is made to switch off all the lights. The role of the ‘magic’ switch would be to remember that a secret combination had been pressed and to inform the master of this at the earliest opportunity. The advantage of this solution is that if I add a new switch to the system – one that I’d also like to be able to control from the hallway – I simply need to modify the central unit, rather than having to modify all the switches that might need to interact with this new one.

4. In both cases (3a and 3b), I would like to be able to control the entire system remotely and monitor it. The monitoring unit will be a computer connected to the local network. It will be possible to view the current status of the entire system via the web. In addition, it must be possible to control any component of the system from this computer (for example, also via the web). In a distributed setup, I simply add a node to the bus and that’s it. In a centralised setup, either this computer will act as the master, or things get more complicated, as I again need to be able to query and issue commands from a node that is not the master.

5. Integration with the alarm system. The alarm system is to be independent. However, my system should have some sort of interface for monitoring and controlling the alarm system. I’ve read that Satel Integra control panels supposedly make it easy to integrate an external device. This device (computer/microcontroller) would be connected to the RS485 network.

6. Integration with the heating system. I’m not sure how this works. Can (gas) boilers be controlled remotely?

7. The system should be open to further ideas (controlling fans, roller shutters, the door intercom, the gate, an IR transmitter for controlling audio/video equipment, etc.)

8. We should consider exceptional situations. For example
- what happens if there’s a power cut, or rather, what should happen when the power comes back on? It would be good if the system reverted to its previous state (lights will be on where they were on before, and off where they weren’t)
- It might make sense for the power supply lines to be connected via a UPS. In that case, perhaps the emergency LED lighting could be powered by the same supply.
- The option to switch quickly to manual control (using some sort of switch). Perhaps it would be necessary to artificially ‘disrupt’ the bus – short-circuit it or cause interference.
- ...

This is my concept for setting up the system at home. And now some questions for you, forum members:

A. What do you think of this in general? Perhaps it doesn’t make any sense at all?
B. Option 3a or 3b, or perhaps something else entirely?
C. Perhaps centralised control using a PLC would make sense? How would that compare to options 3a and 3b?
D. How do my ideas compare to what you’ve already done and got working?

Best regards,
Przemek

There is an opportunity to purchase Simatic PLCs at a low price.
They could be used as home automation controllers.
Details:
https://www.elektroda.pl/rtvforum/topic1205026.html

Re: 3
I’m leaning towards a combined system, i.e. a small control unit identical in every room and one central unit collecting signals from them.
These smaller controllers would locally control the lighting, blinds, audio-visual equipment and everything else within their respective rooms, whilst also receiving commands from the main controller.
The rooms would have small loops in the form of RS-485 buses, whilst the controllers would communicate with the main controller via a standard LAN.
This topology seems logical to me, economical in terms of cabling, and makes it easy to add further rooms by replicating the same subnet.
I’m not yet sure how to control the sockets – whether to run very thin wires to relays, use a bus system with microcontrollers in the sockets, or even run power cables directly from the controller for each room. There’s also a 230V phase-signal control system http://x10.pl , but that also requires controllers in the sockets; it’s quite slow, and I’m not sure if there wouldn’t be issues with isolating the rooms.

arturromarr wrote:

AD. 3
I’m leaning towards a combined system, i.e. a small control unit identical in every room and one central unit collecting signals from them.
These smaller controllers would locally control the lighting, blinds, audio-visual equipment and everything else within their respective rooms, whilst also receiving commands from the main controller.
The rooms would have small RS485 bus loops, whilst the controllers would communicate with the main unit via a standard LAN.
This topology seems logical to me, economical in terms of cabling, and makes it easy to add further rooms by replicating the same subnet.
I’m not yet sure how to control the sockets – whether to run very thin wires to relays, use a bus system with microcontrollers in the sockets, or even run power cables directly from the controller for each room. There’s also a 230V phase-signal control system http://x10.pl , but that also requires controllers in the sockets; it’s quite slow, and I’m not sure if there wouldn’t be issues with isolating the rooms.

It seems logical, but in my opinion there are a few pitfalls:
1. You’ll need to master two transmission systems: 1) LAN and 2) RS485, which will certainly involve more work than just one,
2. The cost of the system will probably increase: a LAN-enabled controller in every room,
3. Problems with programming the end modules – in my opinion, it must be possible to update the firmware

It won’t cost much, as I’ll be building my own little controller based on a microcontroller.
In fact, it’ll be easier for me to build a smaller one that controls just one room and then replicate it for the others.
The central controller might be some sort of industrial micro-PC running Linux on a CF card.
Admittedly, LAN will be a bit of a challenge for me as I haven’t got the hang of it yet, but I like a challenge, especially as I’m planning to run a network cable through the whole house anyway. If I don’t get the hang of it in time, I’ll just use RS485 for all the communication – we’ll see.
For now, I need to choose a method for controlling the devices, as I’m laying the electrical wiring and don’t have a favourite option yet.

eros81 wrote:

3. Problems with programming the end modules – in my opinion, it must be possible to update the firmware

It is precisely for this reason that I am beginning to lean towards greater centralisation. For now, I think it is better to control the lighting centrally, i.e. by running cables from all the lights and switches to a single location and controlling everything with a single device (probably a PLC).

This, of course, doesn’t rule out doing more interesting things with microcontrollers distributed around the house. And indeed, one could then have one microcontroller per room, or perhaps even one microcontroller for several rooms – say, 2–4 additional microcontrollers alongside the central control system for ‘local’ control.

Either way, I’ll definitely be running a bit of extra twisted-pair cable around the house (LAN + telephone + RS485 bus), so it should be possible to expand the whole system later on.

I’m building a single-storey house (thankfully) of around 100m² and, after weighing up the pros and cons, I’ve opted for a centralised home automation system.
Key advantages:
1 – gradual expansion of functionality by adding various components to the distribution board,
2 – very high reliability compared to decentralised systems,
3 – generally lower costs (in terms of labour and money)

PS.
I take my hat off to those who still want to assemble their own little contraptions and plug them into sockets. There are a number of problems with such homemade devices. During construction, there’s no time for such untested ideas – unless, of course, you’re planning to build them later.

You can set the lights to switch on and off automatically. Either fit entry/exit sensors in every room, or turn your watch into a transmitter so your home knows where you are.

Or perhaps we could simply use the Lutron system

As for me, I can see two ‘DIY’ solutions here (without using complete ‘smart home’ kits)

1) Centralised

We plug a Normally Closed relay into the socket (so that, in the event of a control system failure, there is still power at the socket). Add a monostable switch to this, e.g. a microswitch. Run a 2-pair twisted-pair cable to this socket. One pair controls the relay (e.g. supplying 12V from the central unit). The second pair sends a signal to the central unit. When the central unit detects a short circuit at the WE contacts, it changes the state of the WY pair (turning the relay on and off). A 12V relay with a contact rating of 20A is a small block measuring 2x1x1 cm. The microswitch also doesn’t take up much space, so the advantage of this solution is that it fits into a slightly deeper junction box.

The downside of this solution is that each socket requires a separate control line (WE-WY), and the distance to the JC must not be too great, due to the voltage drop which could prevent the relay from operating.

The second drawback is that it is difficult to expand (if we use all the I/O pins on the JC).

Third disadvantage: lack of flexibility and scalability. For example, if we wanted to build a unit to measure the load on a particular socket, this would require different modules.

2) Series topology using Master-Slave devices

In the socket, within an additional junction box, we install a controller containing a relay with 230V operating contacts. We must control the circuit in the controller via a microswitch in the socket. In other words, we press the button, and the controller carries out its task automatically, whilst transmitting information about its status to the Master via the protocol.

I’ll start with the downsides:

Power supply. Its own from the mains before the relay? And what about the transformer that generates heat? Powered from the Master module? That’s an extra pair of wires. For communication, some protocols require 1 pair, others 2 pairs. So the control cable would have to be a 2- or 3-pair twisted pair cable.
And, as I mentioned above, there’s the issue of extra space for the controller, etc.

Advantages

Flexibility. We can replace one such module with another without needing to change the cabling. For example, we can install a temperature sensor, current meter and switch all in one, and control (read) all of this via the Master-Slave communication protocol.

Fewer cables. This is because all devices can be connected in series, as each has its own address. So, in this solution, the cable runs MA-SL-SL-SL (whereas in the previous one it had to be MA-SL, MA-SL, MA-SL).



Perhaps my thoughts will be of some help to someone.

No_idea wrote:

Hi Mischa.

As soon as I’m back from holiday after the 14th, I’ll write to you explaining how to sort this out using, for example, a SATEL INTEGRA series control panel. What you want to do at your place, I’ve already had set up for a long time, both in my offices and in a fairly large house (340 m), and it works flawlessly (I’m renovating the house, so I can always add something if you have an idea). I set up the system as a distributed installation, meaning I have four main nodes, each fitted with INT-ORS expanders and CA-64 EPS + E units (in some cases). Each circuit is routed to one of the nodes to minimise the length of the supply lines. Each node is powered by a separate 5x4mm cable from the main distribution board in the basement. All nodes are fitted with a 17 Ah battery and 12/230 V inverters, as part of the system powers LED lighting (230 V), which also serves as emergency lighting in the event of a power cut. I can control virtually all circuits, including remote control via a GSM4 module and an Ethernet module. The only problem was finding nice push-button switches, as I couldn’t find any – or rather, my wife didn’t like them (they have to be normally open and have a return spring) – so I made them myself by inserting a suitable spring into a standard switch. As well as the switches, the control system receives signals from various sensors: twilight, rain, motion, reed switches, and 4-channel radio systems, Using distributed nodes reduces your costs because, as my colleagues have mentioned, you don’t need to build a relay cabinet; instead, you can create several smaller panels, which in practice will also allow you to fit in standard safety and surge protection devices responsible for, for example, a specific floor (I have the main panel installed in the basement, and that’s where the first surge protectors are fitted). The result of planning the installation in this way is that, in the event of a short circuit, you won’t have to rush down to the basement ‘because the whole building has tripped’, but rather to the distribution box on the floor; the ‘tripped floor’ will be lit by an LED emergency power supply. As well as being convenient, this helps balance the load across the individual phases of the power supply. Of course, these are just some of the many aspects of having a smart installation I don’t have time to write about the rest as I’m off on holiday. I realise that, for example, the control of temperature valves operates on a NO/NC basis rather than continuously, but the room temperature switch works in exactly the same way (once the set temperature is reached, the relay ‘clicks’ and no heat is supplied). And the key factor is the cost of such a solution compared to the prices of branded ‘modules’.

I have a few questions:
Is the lighting switched on and off using monostable switches, i.e. pressing the switch once turns the lights on, and pressing it again turns them off?
If I also wanted to dim the lighting somewhere, how would I go about doing that using the microcontroller?
Controlling the roller blinds when arming or disarming the alarm shouldn’t be a problem, should it?

I see the thread has gone quiet, and you haven’t received a reply (I imagine you’ve probably found the answer since then), but I’ll try to help out a bit here, and I’ll also ask the other users a few questions.

Switching the lights on and off – yes, one click turns them on, two clicks turn them off. If you have five buttons controlling the same circuit, whichever one you click will toggle the lighting state.

Dimming control – this requires a separate actuator and a control element (such as a potentiometer).

Yes. Controlling the roller shutters via the alarm system is no problem at all. It’s an additional setting in the programme. For example, when arming the alarm, all the lighting in the house could be switched off completely, except for the driveway, which would then be dimmed after, say, 5 minutes. The roller shutters would close automatically, the heating would switch to a lower temperature setting, and so on.

Now I have a question. Have any of you seen any wall-mounted switches with built-in temperature sensors? Because in the EiB system, something like that costs around 125 euros, so it’s out of the question. Alternatively, are there circuits small enough that you could hide one yourself in a standard switch, and, for example, how far can the measurement circuit be from the sensor?

Has anyone come across a controller that’s just as cheap but offers more functionality, like the one in the AVT 2895 kit? I’m thinking of something with about 32 inputs and 32 outputs.

Hello, fellow forum members. The issue raised here has been on my mind for quite some time. I have a few observations, namely:
1) I read somewhere recently about a domestic hot water heater fitted inside a shower head. Once I’ve sorted out the mess in my head and remembered where I read it, I’ll post it here.
2) You’re talking about laying kilometres of communication cables, lads. It just so happens that I’ve installed electrical systems in holiday cottages, and if someone wants something like that, it’s hardly a small house. What about communication via the power grid? In industry, this works efficiently and over long distances.
3) I also think there’s no point in reinventing the wheel and designing everything from scratch on a computer. Off-the-shelf industrial controllers that can be adapted as central processing units or specialised controllers are more stable, smaller and easier to install or adapt (PLCs).

mischa wrote:

You know, it’s like this: it’s not strictly necessary for life, just a bit of a whim. Some people will say that if something breaks, that’s it for good. But I’m just trying to get past my own imagination. And me?

I want it all

Just like 30 years ago when I started building my house (long since finished), I felt the same way, but I got over it. I wish you the best of luck.

My concept for the smart home topology is almost complete, and it has to be, as the house is now at the cabling stage.
My main priorities were simplicity (which, consequently, means significantly lower costs) and the system’s scalability.
As I originally planned, there will be a single central controller, working in conjunction with small, identical room controllers.
On the electrical side, each room will have a small panel with a DIN rail to which two – or sometimes one – phases, the emergency power supply line and a constant 24V supply will be connected.The controller will switch the power to the lights, whilst the sockets will be hard-wired. I don’t need to control everything that is plugged into a socket; besides, it’s all too easy to plug various things in there and swap them around. Therefore, if a device is to be controlled (e.g. TV, computer), it will be connected via a special power strip (like a computer power strip) which will communicate with the controller via the 230V line using the X11 system and switch the devices on. This provides versatility, cost-effectiveness and convenience.
On the signalling side, there will be a standard LAN network between rooms and an RS485 network within rooms for terminals and any other devices. All light switches will be connected via a single wire and will short-circuit a resistor of the appropriate value. Very little cabling is required, and the controller will measure the current and know which switch has been pressed. Cables for roller blinds
There will, of course, be an infrared transmitter and receiver for remote control and for controlling audio-visual equipment. In addition, there will be a temperature sensor for controlling the heating.
This setup has many advantages: the wiring is almost standard (normal sockets and only the lighting controlled via triacs), identical cloned controllers (you don’t have to solder in all the components if something is missing), great flexibility (you can connect a new component, e.g. for roller blinds, to the rail-mounted controller),simplified code, which doesn’t have to ‘manage’ the whole house (lights, roller blinds, audio-visual equipment and more) – instead, each controller handles this locally on a smaller scale and reports its status to the main controller, which can then, if necessary, override certain states.
I want the lighting to switch to the UPS line in the event of a power cut and be able to switch on a limited number of lights. The central heating boiler would, of course, also switch to the emergency power supply. Room temperatures would be read by the controller and regulated via solenoid valves.
Given the sheer amount of work involved, I realise it will take several years to fine-tune this, but I intend to implement it in stages, as I’ve become really passionate about this subject.
I think that, for practical reasons, I’ll divide the work into stages.
The entire installation first, as the plaster will cover everything, then the controller for the lights themselves, followed by the central controller, and so on...

Hello.

I won’t go into too much detail as I’ve already posted a description of the project, along with photos, here:

Smart home managed by a PLC controller/

Perhaps I can help someone, or at the very least inspire them

Best regards,
PJ

Great website, thanks for the link. It’s nice to see the finished project.
Many of the author’s ideas coincide with my own, namely using low-voltage switches throughout and a high-voltage installation laid out in a fairly traditional way.
However, I’m not doing a centralised installation but a decentralised one (the piles of cables in the photos make me even more inclined to do so), and I’ll base most of the controllers on DIY Atmel chips.

Pjeter, really nice website, well put together. What puts me off about these projects is the sheer number of cables. A centralised unit, yes, but one that controls smaller controllers – that’s how I see it.
I really take my hat off to the work done on this house:)

I received an email notification about a new post, but it had already been moved to the bin, so perhaps in case anyone didn’t understand my idea.
Of course, any suggestions are welcome.
I’m planning to convert my existing house – a 1980s build with a two-wire system – into a smart home. Unfortunately, running additional cables isn’t an option. I’ve devised a system using multiple controllers, based on, for example, an Atmega 8, in each junction box. Data would be transmitted via the 230 V AC wiring. The central unit would be a PLC. I currently own a GE Fanuc Versa Max.
It’s a lot of work, but nobody said it would be easy

traba wrote:

Pjeter, really nice website, well put together. What puts me off about these projects is the sheer number of cables. A centralised unit, yes, but one that controls smaller controllers – that’s how I see it.

Me too, especially as I’m currently laying out the cables and I’ve already had more than enough of it, and this is only the beginning.
That’s why my approach is geared towards minimising the amount of wiring.
1 control unit distributed across the rooms,
2 analogue inputs, which will allow eight contacts to be controlled using just two cables; each will short-circuit via an appropriate resistor, which, after passing through the A/D converter, can be interpreted as individual switches.
3. Recently, to simplify things (by doing away with the X11 protocol), I’ve been leaning towards running twisted-pair cable to the sockets as well, for the purpose of controlling devices. With the appropriate multiplexing, it will be possible to control 15 devices from a single twisted-pair cable with minimal additional electronics in the sockets themselves. Running a twisted-pair loop to the sockets won’t do any harm for now, and I’ll see how I can make use of it later.
It’s a shame it takes so much work just to see the results.

I’m constantly fed up with this problem of laying kilometres of wiring. I know from experience that the more wiring there is, the easier it is to accidentally damage something later on when drilling a hole for a picture, for example.
On the other hand, in houses like mine, where the wiring is already in place and the plaster is finished, it’s a lost cause. The cost of laying new wiring is simply too high.
The idea of using a 230V AC network for communication seems appropriate to me. I’ve set something like this up using industrial controllers and it worked well. It’s just that I’m having trouble designing the transceiver units. Perhaps one of my colleagues has dealt with this before.

Hello,
As I’m also in the process of designing an installation, I’ve looked into the subject and read through the previous posts. After giving the matter some thought, I’ve decided to go for a wireless control system. I’ve come up with a completely different concept, as wired control causes a few problems, as does centralised control – if the control unit fails, nothing works. Bluetooth is completely out of the question due to its short range and a maximum of eight simultaneous transmitters. I’ve decided to equip the actuators with Zigbee or Z-Wave modules. The main advantages are the mesh network structure, the lack of a centralised system – the modules can communicate directly with one another – and the fact that a fault in a single module only takes that module out of action, not the entire network, and the greatest advantage is the ability to integrate such a solution into existing electrical installations without the need for chiselling or similar work. The actuator modules should fit easily into 60mm junction boxes. In any case, similar solutions already exist – I believe they are based on Z-Wave (by Moeller) – but the price is prohibitive at over 400 for a light switch

Bac, that’s an interesting idea – I’m really looking forward to seeing how the project develops. My main concern is not to have to rip the whole house apart. I hadn’t considered radio communication; I’m not sure how susceptible it is to interference. It’s the summer holidays now, so I’ll be pushing ahead with my idea.

I have found suitable STRX2 modules, which already come with a TCP/IP stack; dimensions including the antenna are 37.75 x 20.5 mm; coverage within the home shouldn’t be a problem as each receiver acts as a repeater; they’re highly resistant to interference and also support a mesh network structure, with control via AT commands and ZigBee Pro implemented (there are also more powerful 18dB transmitter versions; as far as I know, with a directional antenna, they allow for trouble-free transmission over a distance of 1 km). The price is a little high, at around 20 euros for the more powerful version.
http://www.telegesis.com/downloads/general/TG-ETRX2-PM-001-107.pdf
http://www.telegesis.com/downloads/general/TG-ETRX-R212-Commands.pdf
The modules operate at 2.4 GHz

When I find a spare moment, I’ll need to look into Z-WAVE as well; from what I know at the moment, the modules feature an A/C converter and direct triac control with zero-crossing detection (dimmer); the biggest challenge will be the HMI

Baca wrote:

...centralised control too – if the control unit fails, nothing works. .

One of the key reasons why a distributed structure is better.
Firstly, a single failure ‘shuts down’ the whole house (heating, lighting, etc.); secondly, the same situation arises during routine maintenance or upgrades.
A system with small integrated controllers is free from these drawbacks; we can ‘tinker’ with something, or make improvements in one room whilst the rest continues to function normally; at the same time, the main controller oversees the whole system, able to query or issue commands to the controllers under its control.

Thanks for the kind words.

The reason for choosing this architecture is quite pragmatic and smacks of melodrama.

It’s a well-known fact that men live shorter lives than women. Let’s imagine that when we’re gone, our wives will be left with a pile of microprocessors plugged into sockets. After all, no electrician – and in most cases, not even an electronics engineer – would be able to make head or tail of it. (I’m 29, but I tend to think ahead. I really can’t face the prospect of being in my fifties and having to debug the communication protocol for my switches because I’ve messed something up.)

The thing about a centralised system is that a slightly more savvy electrician will figure it out and, in the worst-case scenario, convert the whole lot to bistable relays in an hour.

What do you make of that argument? Huh?

PJ

Added after 4 [minutes]:

arturromarr wrote:

Baca wrote:

...centralised control too – if the control centre goes down, nothing works. .

One of the key reasons why a distributed architecture is better.
A single failure ‘shuts down’ the whole house (heating, lighting, etc.),

Oh, come off it – I could say the same about distributed systems – a short circuit on the bus at any (unknown to us) point brings the whole system to a standstill.

PJ

AVE...

I had a look at this topic a while back, but didn’t have anything constructive to add. Now, whilst familiarising myself with microcontrollers and serial communication systems, a solution occurred to me that is both quite simple and flexible: a system based on 1-Wire. We have ready-made sensors, controllers, a straightforward implementation on popular microcontrollers, and the option of using iButton tokens instead of keys. All peripherals are connected via a single wire (a common ground is also required, but that’s not a problem) to one another and to the control unit (some sort of microcontroller with its own power supply and additional EEPROM memory for storing data on available modules), as well as to simple terminals in each room, which would use the same 1-Wire network to communicate with the control unit. The only drawback is that commands from the terminals must go to the control unit, and only then are they sent to the actuators or sensors. On the other hand, you only need to lay a single cable, as all the components are connected in parallel...

What do you think of this solution?

I once read something about Zigbee and became interested in it; I want to use it in my dissertation – specifically for securing rooms (two, to be precise).I want to put together a SquidBee kit that will have the two features that are most important to me: motion sensors and GSM notifications to my mobile phone. However, I’m not sure which modules are best (and which will be essential) to order so that they can be used and have the features I need. From what I’ve read and researched, I’ll (probably) need these modules

http://www.libelium.com/tienda/catalog/produc...0&osCsid=2edbadabb311374af45aa4235e7e6252

and

http://www.libelium.com/tienda/catalog/product_info.php?products_id=59

and my question is whether I’ve chosen the right kit and whether I need to add anything else for it all to work together :/ Thanks in advance for your advice, because on online marketplaces and in shops, people haven’t got a clue about Zigbee, in fact, they’ve never even heard of ‘such a thing’.

And I’ve another question: will this be sufficient for motion sensors:
http://www.libelium.com/tienda/catalog/product_info.php?products_id=52

AVE...

It would work out cheaper for you if you bought a bare microcontroller and wrote the software yourself. You could connect the sensors directly and wouldn’t have to spend money on an Arduino. I’d use a PIC16F505* (4 zł at TME). It has enough processing power to work with sensors and a GSM module via I2C or 1-Wire...

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* – because I’m finishing off a programmer for PICs...