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

No, OK – I’m also putting together a bit of a makeshift setup, but I just want what’s necessary and makes life easier.
It’s probably not possible to switch the TV on via a socket (it’ll just go into standby).
As for the sockets, I’m leaning towards a wireless system: one or two sockets that plug into fixed points wherever they’re needed...

Hello
Switching off the power at the 230VAC sockets is a good idea and environmentally friendly. Most audio-visual equipment doesn’t even have a power switch and continues to draw electricity unnecessarily.

I’m no stranger to this topic either. I’m finishing off the final touches at home, connecting the last few cables… and there are a few minor issues cropping up . Fortunately, most of them can be worked around somehow, but you’ve got to be resourceful.
So, what did I forget/what did I do wrong (and, whilst I’m at it, here are my ideas for ‘smart home’ solutions):
1. I ran two coaxial cables from the TV/radio distribution box to the satellite dish mount – it later turned out there should have been four... then I could have had a separate tuner in every room, which would have worked with a single QUADRO converter. This should still be fixable, but I’m warning others.
2. Some of the lighting in the house is switched on via relays located on the distribution board in the boiler room. Separate cables were supposed to run to the switches, but we didn’t lay enough of them . We then had to run twisted-pair cable to the switch panel under the tiles after the screed had been laid.
3. Another great idea worth trying: LED night lighting. The idea is to have white LEDs fitted into skirting boards along the walls, which switch on only at night (via a twilight sensor) and when motion is detected (e.g. if I’m walking to the bathroom, they’ll come on – using sensors from the alarm system and a properly configured control panel). And of course, I forgot to run the cable from one part of the house to the other... I went to such lengths to run it But I managed it yesterday and no one will notice it, even though it was laid over the finished floors.
4. We cleverly ran the cable from the alarm siren to the boiler room instead of to the alarm control panel… It’s a good thing I realised in time.
5. At one point, it occurred to me that it would be worth fitting a ~230V socket outside, near the roof. It could be used in the future to connect Christmas decorations or something else. Controlled by a relay, of course.

My entire installation is controlled by a Festo FEC-640 controller I bought on Allegro. The most important features are its Ethernet connection and web server. For now, it only handles the simple task of switching the lights on and off (it acts as a multi-bistable relay). In future, it will have more functions, such as simulating the presence of household members, monitoring the state of the house via the Internet, control via the Internet (all non-critical power circuits in the house are routed through an NC contactor connected to the controller, which will allow these individual circuits to be switched off remotely). In addition, it has an RS-232 port, so I can easily expand it with my own actuator modules.

Dar.El wrote:

Hello
Switching off the power at the 230VAC sockets is a good idea and environmentally friendly. Most audio-visual equipment doesn’t even have a power switch and draws current unnecessarily.

I wrote earlier that I’m not talking about centrally switching off the appliances (a contactor will be used here), but about controlling individual 230V sockets – that’s what I consider pointless (apart from one or two exceptions controlled by radio or via the power grid).

I’ll quote myself here, as at least something is happening in this thread :

_Tomaszz wrote:

I’m also planning a ‘quarter-smart’ installation within a reasonable budget (max +25% of a standard ‘top-of-the-range’ one) and I’ve asked myself the following questions:
1. I need to define the tasks such a system is meant to fulfil; in other words, what I want, and what I can do without
2. What (or who) is the system supposed to communicate with?
3. What will happen in the event of a system failure (e.g. after a storm) and how long can I manage without it?
4. How can I implement manual control?
5. How can I go about replacing the system (in 20 years’ time, today’s system will be fit for a technology museum)?
6. How to switch back to a traditional system (if I sell the house or am no longer around) so that the house can function without me.
7. How to build the system in stages: construction (lighting must be in place) -> 1–2 years with essential functionality -> completion and full system functionality.
8. Finally – which system (or which controller) and which network topology to choose, taking all of the above into account.

I’ll answer that another time...
....once I’ve thought it all through

Krollew,
I’m also thinking about 12V LEDs: night-time lighting for corridors and stairs (from dusk until midnight) and activated by a motion sensor at night (when I’m feeling parched).
With just 30 watts, you can light all the passageways and have emergency lighting if needed. Plus, one LED lamp in each room as emergency lighting.
I won’t be fitting emergency power sockets (so the kids don’t drain the batteries with their nonsense), except for one in the hall – to charge my phone and charger.

You must be setting up some sort of new Pentagon department. Amongst all these systems, I can’t see any plumbing or fire-fighting systems. You’ve already got the controls for the window and door blinds. I saw some window panes at the trade fair in Poznań which become opaque when a voltage is applied to them (yet another system).

Diagran6 wrote:

I reckon you’re setting up some sort of new Pentagon division.

Yeah, as part of the missile defence shield

Diagran6 wrote:

window panes that become opaque when an electric current is applied to them

That’s quite a luxury given the current circumstances, but I must admit – it’d be brilliant, even if just in one room. The one where you watch films

Added after 12 [minutes]:

MirasH wrote:

Hello
A smart home should not be without a mechanical ventilation system. Depending on its complexity, such a system may include a heat recovery unit and an air conditioner. And this is where there is scope for innovation when it comes to controlling the damper motors of individual devices.

I must have missed your post somehow. Sorry

Yes. There’ll be a heat recovery unit, plus a ground-source heat exchanger. The control system for this is ‘proprietary’. You get a small LCD panel for the air handling unit via RS485, which you mount in the hallway.

Some LCD partition walls don’t need to be painted, and the scenery changes depending on the music, or perhaps the temperature, the weather or the time of day.

Diagran6 wrote:

It looks as though you’re setting up a new Pentagon division. Amongst all these systems, I’m missing the plumbing and fire-suppression systems. You’ve already got the controls for the window and door blinds. I saw some window panes at the trade fair in Poznań which become opaque when a voltage is applied to them (yet another system).

I read about these panes about six years ago, but I can’t for the life of me find them. Who makes them or sells them? Give me a lead.
I was at the trade fair too, but I didn’t manage to see everything.

Hello!

There are also special flexible films that glow when a voltage is applied. Once these films have been fitted into walls, or even into household furnishings, you can create, for example, interesting night-time or emergency lighting. Unfortunately, glow-in-the-dark films, LCD screens in walls, and those ‘fancy’ windows are, given our national circumstances and for the time being, ‘inventions’ probably only accessible to a small percentage of citizens with a REALLY fat wallet.

Best regards

These panes were exhibited by a company that I think manufactures lifts, or lift components. They were fitted to the sliding doors of a lift mock-up. The Securex trade fair. A company dealing in fire alarm control panels also had them on display.

Ambitious plans… but what about the implementation? You need a lot of experience to set up such systems so that they run fault-free and exactly as we want them to… issues with interference soon crop up…etc., and in the event of nearby lightning strikes during a storm, that’s when things really get I’d advise you to think about this

The simplest way to control sockets is via the 230V mains supply. By selecting the right flush-mounted boxes and miniaturising the PCB, you can have a controllable (on/off) contact with current monitoring (current transformer). No cables – their cost will be covered by the controller and transceiver. You can safely disregard I2C and 1-Wire for power applications, as these are local buses. If you really insist on using a wired bus, then RS485 or standard Ethernet. And from there, on to the devices.

Hello,
Great ideas....
My idea was that, when I leave the house, I could switch off some of the devices connected to the mains. I’ve already laid the cables and planned out where the devices will go. The cables for controlling the contactor are positioned by the entrances.
I’ll connect everything I want to switch off when I leave the house and switch on when I get home to the contactor.


My only problem is which contactor to use and what specifications it should have???
I’d appreciate some advice.

Kind regards

A device like this can be a great help when building a smart home:

http://www.sklep.insbud.net/product_info.php/products_id/91

A very reasonable price for what it offers.

Hello,

I’ve just come across this thread and I must admit it’s very interesting, all the more so as I’m currently planning the wiring for my home to accommodate future smart home installations.
My thoughts are as follows:
- first, I need to install a ‘standard’ 230V system in such a way that, over time, I can (in my case) convert it to a system where individual points are controlled
- the system must be decentralised (a central controller creates a single point of failure, and that is unacceptable)
- all components – i.e. control units and actuators – must communicate via a single bus (after all, I’m not going to run twisted-pair cable to, say, every point I want to control); I’m initially thinking of RS-485. At present, the price of a microcontroller is negligible, so you could fit such a circuit into, say, any flush-mounted box.
- In the event of a failure in any part of the system, it must be possible to bypass it quickly (e.g. by simply cutting out the room’s lighting control circuit and connecting a standard light switch. The circuit can then be repaired at leisure whilst maintaining the basic functionality of the light switch).

I’ve only got one sticking point. How do I power such a distributed microcontroller system???
I’ll be using 2 pairs on the RS-485 bus in full-duplex mode. Assuming the cabling is twisted pair, that leaves 2 pairs. I could then run 5V through them (which would give a total cross-section of 1mm² for the positive and earth). Will that be enough? Or do I also need to run separate power cables for the circuits in parallel to the bus?

I’d be grateful for your opinions.

Added after 23 [minutes]:

Of course, as stated:
‘- first, you need to build a “normal” 230V installation in such a way that, over time, you can (in my case) convert it to a system where individual points are controlled’

I’m referring to the 230V cables, virtually all of which will run from the main distribution board (no junction boxes), the bus cable running through all possible control points, and possibly that unfortunate separate power supply (5 or 12 V)

DrWycior wrote:

I’ve only got one problem. How do I power such a distributed microcontroller system???
I’ll be using 2 pairs on the RS-485 bus in full-duplex mode.

RS-485 in full-duplex mode uses 5 wires – that is, 4 data wires plus GND – so using a 4-pair twisted-pair cable will be the best solution;there will always be one pair left in reserve, e.g. in case a pair is damaged whilst laying the cable, or it can be used for other purposes

Best regards

OK. There won’t be any high-speed data transmission there, so I reckon even a unidirectional connection will suffice. So, 1 pair + GND, right?

So, can the remaining wires be used for a DC power supply?

I’d really prefer not to run an additional power supply in parallel with the twisted pair, but if there are going to be problems with this later on (insufficient current capacity, voltage drops over a distance of several hundred metres), I’d rather sort it out now than end up with non-functional cabling later on.

With half-duplex RS485, three wires (A, B, GND) are sufficient. I know from experience that with CAT5 twisted-pair cable in an RS485 setup, I can run a 5V power supply over a single pair to the microcontroller (Atmega16) over a distance of 300mb, and the voltage at the other end will be 4.5V. I’m just giving an example here for an AVR with 4xDS18B20 sensors, and the whole thing works fine even in winter, when voltage drops along the cable are greater. You can always use the spare pair you have left and run the power supply over two pairs (e.g. 12V), then add a 5V regulator at the end to power the microcontroller.

Thanks for the quick reply.

In your case, it’s one controller.

The problem is that, in my setup, there could be up to several dozen microcontroller-based circuits operating on a single bus in the future.
I’m afraid that even if I use one pair for + and one for GND (i.e. 2 x 1mm²), with a 12V supply, such cross-sections might not be sufficient to power the whole system.

Does anyone have any experience with this seemingly trivial problem? I know from experience that a good power supply is essential, and even minor faults can lead to the entire circuit malfunctioning.

Added after 28 [minutes]:

Someone wrote:
“Can someone explain to me why you’d want to control 230V sockets (each one individually)?”

Before I came across this thread, I had the following idea:
I have a TV in my living room, and as there are quite a lot of windows in that room, watching TV on a bright, sunny day can be a bit of a problem.
So I came to the conclusion that I could set up a system like this: in the socket to which the TV is plugged in, there’s a microcontroller (uC) that checks (based on current draw) whether the TV is switched on. Then, the same microcontroller queries a light sensor (positioned near the TV) for the ambient light level. If it’s too bright, a signal is sent to the roller blind controller to partially dim the room to a level acceptable for watching TV.

In this case, although there is no control over the socket itself, the current draw from that socket is monitored.

I find this interesting – what do you think?

Do two things and you’ll be ahead of everyone else.
1 When you leave for work, your smart home will tidy itself up.
2 When you get home from work, your smart home will be waiting for you with a hot dinner. Which, of course, it has prepared itself.
If you could manage to implement these two functions for a smart home, that would really be something.

Added after 13 [minutes]:

Make it so that when you leave for work, it cleans up after itself.

Hello,

You know, Gaz22, this thread was started by someone who wants to do something interesting, and I fully understand that. I’m also passionate about electronics myself, and on my spare evenings I like to tinker with things in this area.
If the result is going to be something functional for the home, why not make use of it?
If you’re not interested in it, why are you criticising others and cluttering up the thread with cynical sarcasm?

Added after 49 [seconds]:

Apologies for the mistake, qaz22.

In my opinion, lads, if you want to set up a smart home, you need to think carefully about what you want and how much money you’ve got. I know from experience that you can’t predict everything; it’s best to do it all in one go, but very few people can afford that!!!
These systems are expensive, let’s face it!
Automation isn’t limited to the house itself, after all – you might also want to heat the path from the garage to the house,
heat the roof and gutters to prevent them freezing, and so on.
You can automate everything – it’s just a matter of time and money.
To start with, you need to think about what you actually need: do you want to control every single socket and switch, or would it be better to switch off all the unnecessary ones with a single switch, for example?
Unfortunately, that’s how automation projects are often designed to cut costs

qaz22 wrote:

Do two things and you’ll outdo everyone else.
1 When you leave for work, your smart home will tidy itself up.
2 When you get back from work, your smart home will be waiting for you with a hot dinner. Which, of course, it has prepared all by itself.
If you could manage to implement these two functions for your smart home, that would really be something.

All you need is one Chinese woman.

Controlling the lighting and sockets can be done very easily using a DIY and inexpensive method. You simply fit a double socket box – these are readily available to buy. Then run a 2- to 4-core twisted-pair telephone cable to the second one – costing less than 1 zł/m. You can decide later whether to control a socket or a light – you simply fit a microcontroller with a triac. However, it’s also worth fitting a temperature and light sensor onto its circuit board (one per room) for the fire alarm system, burglar alarm, lighting, roller blinds and heating.
The issue of LAN is problematic – on the one hand, Wi-Fi is now so cheap that it isn’t worth running cables all over the house; on the other hand, it isn’t worth risking cancer caused by exposure to high-frequency radio waves.
It’s worth linking the whole system to a mobile phone – the simplest solution is two-way communication via text messages using an old, cheap Siemens handset.

DrWycior wrote:

The problem is that, in my setup, up to several dozen microcontroller-based circuits may end up operating on a single bus in the future.
I’m afraid that even if I use one pair for + and one for GND (i.e. 2 × 1 mm²), with a 12V supply, such cross-sections might not be sufficient to power the whole system.

Bear in mind that in a traditional ‘twisted pair’ cable, the cross-sectional area of a wire is roughly 0.2 mm².

For data transmission in the scenario you’re describing (multiple chips, so likely a multi-master bus), you only need one pair and nothing more. For power, you can use two of the four pairs in the cable, leaving the fourth pair as a reserve. In that case, 200 metres of cable will present a resistance of approximately 19 ohms. If you place a power supply, say 30 volts, at the start of the cable and draw a current of 1 ampere at the end, you will have 11 volts at the end of the cable.

Two things need to be noted:
1. the power supply circuit in each device on the bus should be capable of operating within a sufficiently wide range of input voltages,
2. the data transmission circuit (transceiver) must be resistant to high common-mode voltages, as the reference ground for all the circuits will be the negative supply rail.

alecki99, thanks for your interest and reply – I’d already given up hope that anyone was still checking this thread .

As far as I know, the cross-sectional area of a single core in the twisted pair cable is 0.5 mm² (that’s what the manufacturer and the cable supplier – from whom I buy twisted pair cable professionally – state). Where did you get the information that it’s 0.2?

I’m wondering whether to use a 4-core YDYP cable (4x1.5 mm²) for the electrical installation and use that fourth core (+) and the protective earth (GND) to power all the circuits.
I’m not sure if it’s correct to use the protective conductor as the GND for the microcontroller’s power supply.

I’d be grateful for any advice.

DrWycior wrote:

As far as I know, the cross-sectional area of a single wire in a twisted pair cable is 0.5 mm² (according to the manufacturer and the cable supplier from whom I buy twisted pair cables for professional use). Where did you get the information that it’s 0.2?

A standard conductor is approx. 0.5 mm in diameter, i.e. 0.2 mm² in cross-sectional area.
This type of computer cable is perfectly suited for signal transmission – I’ve temporarily connected a certain transducer 20 metres away from the controller (a very sensitive analogue signal – every 0.001 ohm affects the result) and there are no issues.
You can always use a slightly thicker professional control cable, e.g.:
8 × 0.25 mm² in a shielded cable – 79 Ω/km – 3.5 zł/m
6×0.34 mm² shielded – 57 Ω/km – 3.3 zł/m
8×0.50 mm² shielded – 39 Ω/km – 5 zł/m
For comparison:
computer cable 8×0.2 mm² with shielding – 94 Ω/km – 1.2 zł/m
OMY 2×0.5 mm² – approx. 37 Ω/km – 0.90 zł/m
YDY 3 × 1.5 mm² – approx. 13 Ω/km – 2 zł/m
YDYP 4 × 1.5 mm² – approx. 13 Ω/km – 2.7 zł/m
YDY 5×1.5 mm² – approx. 13 Ω/km – 3.4 zł/m
Telephone cable with YTKSYekw shielding, 1×2×0.50 mm – 98 Ω/km – 0.45 zł/m
I propose the following solutions, assuming that a standard house has a floor area of 64 m², i.e. the longest cable will be 25 m, and the automation power supply will draw 1 A:
1. YDY 3×1.5 mm² as power + computer cable (1 pair for communication + 3 pairs for power supply) – voltage drop across the automation power supply – 1.6 V – cost 3.2 zł/m
2. YDY 5×1.5 mm² (power + automation power supply) + telephone cable – voltage drop 0.66 V – cost 3.85 zł/m
3. YDY 3 × 1.5 mm² (power) + control 6 × 0.34 mm² (1 control pair + 2 power pairs) – voltage drop 1.4 V – cost 5.3 zł/m
4. YDY 3×1.5 mm² (power) + OMY 2×0.5 mm² (control circuit power supply) + telephone – voltage drop 1.8 V – cost 3.65 zł/m
The cheapest solution is the one previously proposed (solution 1), but there will be a relatively large voltage drop – over 1.5V. The smallest voltage drop will occur with solution 2 – only 0.7V, and the price is also attractive.
For comparison purposes, the prices of cables and wires are taken from a single distributor. Of course, on Allegro you can buy ‘copper-plated’ wires – i.e. those with a 20% copper content – much more cheaply.

DrWycior wrote:

I’m wondering whether to use a 4-core YDYP 4x1.5mm² cable for the electrical installation and utilise this fourth core (+) and the protective conductor (GND) to power all the circuits.
I’m not sure if it’s correct to use the protective conductor as the GND for the microcontroller’s power supply.
I’d be grateful for any advice.

You must not use either the protective earth or the neutral as a power supply for automation circuits! Firstly, for safety reasons – 230V could flow through the automation system in the event of a fault in the electrical system in your own home or a neighbour’s. Secondly, the residual current device (RCD) will trip.

WD40, many thanks for your help. That’s exactly the sort of answer I was looking for.
I’ll most likely use 5 x 1.5 mm² live wires and 5 x 2.5 mm² neutral wires, and I’ll use this cable for the electrical installation. I’ll probably add a standard twisted-pair cable as well.
The cost of this solution is a bit higher, but it’s the most versatile option.

WD40 wrote:
You must not use either the earth or neutral wire to power automation systems! Firstly, for safety reasons – 230V could flow through the automation system in the event of a fault in the electrical system in your own home or a neighbour’s. Secondly, the residual current device (RCD) will trip.

After giving this issue a bit more thought, I came to exactly the same conclusions.

There is another option for powering such a distributed uC system, which I had already considered earlier.
Namely, simply to provide a standalone power supply for each circuit; after all, there is a 220V AC supply at every point where an automation circuit will be operating.
There is, however, one problem. How can this be done without a transformer or a converter (as they simply won’t fit inside a flush-mounted box, and besides, their components generate heat)?
Admittedly, the current draw of a single circuit is negligible, so the current capacity of such a power supply needn’t be high.
So the question is: are there any integrated 220V AC/5V DC voltage regulators that I could solder directly onto the microcontroller (uC) board and use to power each of the circuits from there?

A solution with a standalone power supply seems like a good idea, as this is precisely the approach used in the LCN system (the second major player on the building automation market after EIB). Have a look at www.lcn.pl (the Polish representative), if you haven’t already. According to the catalogue specifications, the power consumption of the LCN flush-mounted module is less than half a watt.

But perhaps it shouldn’t power the circuits from 230V after all, but from a lower voltage, and run the power supply via two pairs of UTP twisted-pair cable. This is the cheapest cable and, although it has a small cross-section, it might work for a relatively small installation. I suspect that the efficiency of the converter should be relatively high given the very low power consumption, and this is a significant consideration. Try working it out. Do you know roughly how much power each of the distributed circuits will draw?

You know, alecki99, there’s one thing I’m worried about. Namely, that if I just run a twisted-pair cable and it later turns out that it’s not enough, then – as they say – I’ll be in a right fix. In that case, my only option will be a 230V power supply, which means using some sort of power converters.

Admittedly, alarm systems work on a similar principle, where the power runs through a single pair of 0.5mm-diameter cable, and that’s enough to power even several detectors (each one draws about 14–25mA) but those are tried-and-tested systems.

I’m increasingly leaning towards the solution of simply running a separate YDYP 2x1.5 mm² cable in parallel with the twisted pair to carry the 12 V power supply, and using this ‘bus’ to connect all the automation points throughout the house.
That way, I’ll end up with a second small 12VDC distribution board for the automation system, situated right next to the 230VAC distribution board.

What do you think of this? alecki99, thanks for the link – I’ll have a look at it straight away.

Added after 1 [hours] 17 [minutes]:

By the way, it’s interesting to see how the LCN system manages to power each circuit from 230V whilst keeping the module thickness at 2cm.
Have a look at their website for the device specifications.