Microcontroller based power switching revisited in 2024

[TerryE]

I started a related topic, IoT / microcontroller based power switching back in 2019, but a lot has changed in this last 5 years both in terms of the commercial off-the-shelf (COTS) products available to approach this; in my own attitude to doing custom development; and lastly in the actors on the forum that might want to input their thoughts.  There is also a steady stream of new members who want to implement this sort of approach. 

 

There is a spectrum of options here, so let me list three sweet spots, and what I want to do in this topic is to focus discussions on the last one:

 

• A full IoT HA installation.  Here I am talking about a Loxone-type system, the sort of installation that @jack has and where you want a soup-to-nuts home automation. This sort of system needs professional installation and certification, so you are probably talking about maybe £5K+ for the kit and another £5K for professional services, so quite an expensive option.
   
• Consumer-grade IoT devices.  At the other end of the spectrum, there is a huge range of end-user kit and devices that are treated as outside the scope of Part P notification and certification.  This area has really blossomed in the last 5 years with the explosion of systems such as the RPi-base Home Assistant, a plethora of ZigBee and Wifi smart devices, many also Alexa and Google Home enabled or with other cloud-service enabled functionality.  Technically aware homeowners can use these to do a lot of home automation without falling foul of Part P Building Regulations.  However, in terms of power devices whilst the standard UK socket is rated for 13A and can comfortably take this load for short durations, I personally would never leave even a 2kW device plugged into one for long term unattended use.
   
• Installation falling with the scope of Part P.  In my case I have 3 × 3kW resistive heaters and a UFH pump that I want to control safely and legally, and at a sensible cost  (that is without needing to install a Loxone system), but this work definitely needs to integrated in the house's wiring fabric and must comply with Part P requirements.

 

So what are my options for work in this last category? (@ProDave @Nickfromwales and the other relevant trades experts on the forum, I would value your views / sanity-check  on what I say here.)  First some observations.

 

• In my case I have a good relationship with an electrician who did my house wiring and is Part P approved for signing off wiring modifications. He is a good but traditional sparky so I would need any mods to be well within his comfort zone for him to sign off.  I am more than happy to leave the 240V stuff for him to do.  In his case he is quite happy to wire up components such as relays so long as they come from a reputable UK supplier and have the correct certification paperwork, but he definitely would be a lot more unwilling to put his name  to some power connectors sourced directly from China such as the SONOFF Smart Stackable Power Meter range even though these do have proper CE certification, and good build quality.
   
• As far as I read it, almost any wiring that is part of the building fabric falls within the scope of Part P.  The explicit exemptions include coms wiring such as telephone lines, but even PoE is a grey zone. However, the primary aim of Part P is to ensure Fire and Personal Safety and there is a category Extra Low Voltage (ELV) that covers wiring such as 24V DC circuits,, and the risk here is very low (but still not-zero).  The main point for me is that my electrician is a lot more relaxed about 24V (or lower) control circuitry.
   
• In my last topic on this, I ended up using DIN rail-mounted 240V 20A Crydom SSRs that are driven by 5V TTL logic to do my power switching, but TBH they have proved a total PITA, as they throw out about 60W waste heat at full load and so they run just so hot, which then causes various thermal problems.  In retrospect since I am switching 12A AC1 loads, a decent relay is perfectly good enough such as the Finder 22.21.9.024.4000 are fine for this job and they only chuff out 3W.  (AC1 includes straight resistive loads such as immersion heaters. Heavy AC7b loads such as motors or ASHPs are a different ballgame and would probably require using a contactor).  These relays are driven by 24DC coils, so I can drive all of my control logic from a single 24DC supply.
   
• So how do I implement the 24V DC control circuitry?  One option would be to add a MOSFET relay driver hat to an RPi, but my preference would be to stick with a dedicated I/O front-end processor, such as the Kincoy KC868-A8M switch, but my current choice is the Sonoff 4CH Pro R3.  Both can run off a 24V supply and can drive 24V DC control logic.  Being ESP32-based they both can run standard Open-source Tasmota, ESPHome and ESPEasy firmware builds.  All three of these connector apps support MQTT as well as allowing you to set up failsafe watchdogs on any relay open commands.

I have more to cover, but I'll break his post here for others to comment.  @MikeSharp01, that includes you 🙂     

 

 

 

Edited January 26 by TerryE

[ProDave]

I am not the best person to comment on part P as it does not exist in Scotland.  But my understanding is it only applies to new circuits, and work in special locations like bathrooms.

 

So if you have an existing circuit feeding say an ASHP and you want to modify that by changing the fixed wiring, that is outwith the scope of Part P so just get on with it.

 

My choice for power switching from a microcontroller (Arduino in my case) was a solid state relay.  That has been hapilly pulsing mu thermostat for years.

[joth]

I think you have two distinct questions here, one about where to put control logic (Loxone, home assistant, ifttt, Google home, tuya cloud, etc etc) and the other about how to switch heavy loads in a safe and ideally low certification overhead way.

The crux seems to be the latter

 

What's the switching frequency? If more than once per 10sec I'd lean towards an SSR. Else a good quality relay or contactor 

 

 

https://www.wago.com/gb/relay-and-optocoupler-modules/relay-module/p/788-304

 

https://shellystore.co.uk/product/shelly-pro-1/

 

(Regarding Loxone I know at least 5 of us on here DIY installed it, but I think that's orthogonal to your main question)

 

 

[TerryE]

@ProDave, in our case Jan wants to say goodbye to the SunAmps and on balance I've come to the same conclusion.  So we have decided to replace them with an OSO Super Xpress UVC which won't fit in our current CH+DHW services cupboard, and worse the DHW pipe runs will have to go through where my instrumentation panel sits, hence I need to relocate this as well.  The plumber can do the G3 certification, but the power circuits currently running to the SunAmps will need rerouted and this technically needs to be installed and certified by a Part P approved sparkie.  In England, home owners can no longer self-certify Part P work.

 

The scope of English Part P is all fabric wiring, and yes areas like bathrooms have all sorts of extra safety considerations, but the basic principles remain: the wiring should be safe, and it should not introduce fire risks.

 

This usecase is something that a few members here have raised, so I thought it something worthwhile to discuss first here on the Boffins forum and then write up as a blog post.     

[ProDave]

I hope one of the English members who are part P can come and comment.  Unless things have changed, it is only new circuits or work in special locations.  So if you have a power circuit feeding a sun amp, then altering that circuit to feed a different how water tank in a different location is not notifiable.  Please someone correct me if that is not the case?  

[TerryE]

@joth  yes you are correct, these are two separate facets, but there is a third: it would be nice if I could implement and document this as a standard template that others could adopt / tweak as needed. 

 

I already have a mature Node-RED app doing my CH + DHW control, etc.  This boots a minimal Raspbian server from an OverlayFS root, but with a USB attached SSD for persistent app data.  This also interfaces to my Home Assistant set up via MQTT; I've used HA for years, and in the early days it was pretty flakey hence I settled on this split where the lean dedicated Node-RED CH+DHW system is "mission critical", leaving HA for optional goodies such as driving all of my other IoT devices where the world isn't going to end if they are out for a day or two.

 

All of my house services are hosted locally on my LAN, so nothing will break if I lose WAN access.    The CH+DHW RPi currently uses a couple of home-brew ESP8266 boards running Lua Firmware as I/O processors.  I want to replace these with COTS H/W running a common firmware app such as Tasmota.

 

And yes, the other aspect is how to switch heavy loads in a safe and ideally low certification overhead way that your typical local sparky would be comfortable wiring up and signing off.

 

As far as the relay switching wear is concerned, yes you make a very valid point.  The Finder relays have an electrical cycle life of around 50k cycles at 3 kVA, and an upper bound on my switch rate is maybe 10 open/close per day, so this equates to around 30 years -- which will outlast me.  

 

The challenge with SSRs is that they typically have around ½-1 % switching loss which is a lot of heat in a small device when you are switching 3 kW. There is also the double whammy that this loss gets worse as the SSRs heat up.  The  Crydom SSRs have finned heat sinks but still run at 50+ °C, so you really need fan assisted cooling if in a closed enclosure.  If I had to use SSRs again, then I'd switch to the surface mount form factor and bolt them to a bloody large steel plate to act as a heat sink. 

 

Out of interest, am I in the right ballpark for my estimated Loxone costs?  Thanks.

 

Edited July 5 by TerryE
Life of relays wrong

[MikeSharp01]

Hmmmmm. @MikeSharp01 responds It's a bit of a mine field. I have a deep aversion to anything that buys me into a technology win by any single supplier so I won't  be buying anything like Loxone that won't work with everything else if I can avoid it. I think the open source stuff that is here to stay (MQTT, RPi, Node Red, ifttt) is a better route and will be less of a single point of failure if a single supplier goes out of business and they teach python to 7th graders now who could probably maintain a neatly documented code setup. I have just finished pulling 1500m of CAT6 cable all over out build to support POE building automation and although all the light switches are traditionally wired once they get back to the panel it's another world I could have run the whole lot as 24V but decided to go 240v and feed them all into suitably isolated inputs to the RPi. Realy just so a normal sparky could pull them off there and wire them directly if push came to shove. As it is the outputs are some relays and whitewing dmx control of 240V led lights everywhere.

 

From a high current 240v controlling point of view I am not sure I want contactors banging about in the power control panel which is in our Utility room - neither would I want to force cool the panel or have it produce heat I don't need in a very well insulated house. 

 

I guess I could put the contactor for the ASHP in its panel outside. Inside the house the number of 13A loads is limited to immersion heaters which are not the most corrosive of loads for a decent relay. I guess I tend to align with @joth on when to use SSRs. I have also fallen to thinking that I don't need to control sockets because the devices plugged into them are or will be smart so can look after themselves. We have Zigbee and Z-wave hubs planned so if it won't talk to one of those or vanilla wifi we won't be buying that brand of fridge/ cooker etc.

 

 

[TerryE]

@MikeSharp01, the Finder relays discussed above are fine for switching 3kW AC1 loads such as Willis or Immersion heaters as well as lower power AC7b loads such as your UFH manifold circulation pump. The issue is that these use 24V DC coils, so you need to switch 24V DC from your PRi and this is better done with an external  Frontend IoT processor such as one of those listed above.  

 

One of the nice features that you can implement with a FEP is failsafe shutdown, for example any relay close command automatically times out after 35 min, so any long duration close must be reissued every 30 mins.  This is easy to do in HA or Node-RED, but if the RPi dies when any relay is closed, then it will still timeout and shutdown/open safely rather than staying open (potentially for days) until you can do a manual intervention.

 

The Sonoff 4 port switch does have internal relays but these have a decent spec and will far outlast the power relays as they are only switching ~50 mA to power the main relay coils.

 

I don't think it sensible to switch something like a ASHP directly; better to use one with a MQTT or CANbus I/F to do this programmatically.  That Kincoy IoT F/E board above includes a built-in CANbus I/F as well as 24V DC MOSFET drivers.

 

If I was using Wifi for such "mission critical" control then I would configure the RPi to act as a MQTT (Mosquito) host and use the Wifi in Station mode and run a private channel for an IoT LAN for the FEP(s) and any other Tasmota devices needed for control.  That way, you'd be independent of the main router and Internet.  

 

Edited July 5 by TerryE
Experience has proved that even a 50W AC7b load will quickly knacker this relay

[Mike]

2 hours ago, TerryE said:

In my case I have 3 × 3kW resistive heaters and a UFH pump that I want to control safely and legally, and at a sensible cost

I have a similar problem - switching 2 Willis heaters + pump + DHW (probably a SunAmp due to lack of space) - and I need to get it signed off in France by the independent electrical installation inspectorate (Consuel). It won't be up and running for a few months, but I have solution that should work, in theory.

 

I'll be using a DIN-rail mounted Shelly Pro 4 PM in the consumer unit, providing 4 independently switched channels, one for each of the items above. Since the Shelly has limited load-switching capacity, it will switch 3 regular Legrand CX3 412558 silent contactors* in the consumer unit, with only the pump being directly controlled. In fact, as I'm limited to a 52A mains supply, there will be a Hager 60060 load-shedder between the Shelly and the contactors, monitoring the smart-meter and temporarily switching out the contactors when necessary. Provisional schema below.

 

The Shelly can be operated in several ways (demo on YouTube), including manual buttons and via an app or web browser over Wifi, Blutooth or Ethernet. That includes the option of creating a weekly schedule so, with the addition of a thermostat, it would be possible to run everything in a similar way to a regular central heating controller, though I don't plan to do that. The Shelly also comes with an MQTT interface (documentation), so it can also be controlled using Node-Red / Home Assistant. Like you, I plan to run that on a Pi + SSD, with a PiJuice micro-USP with auto-reboot capability.

 

From the software side this should give plenty of flexibility while, from the hardware angle, everything looks like it belongs in a regular consumer unit, so hopefully no sign-off problems. And, if the Pi fails (and while I wrestle the software into shape), the heating & water can still be operated via the Shelly.

 

*25A resistive / 10A inductive, 230V power & control circuits. There's also a model with 24V AC control.

 

 

[TerryE]

@Mike, FR building codes are another ballgame.  You might want to consider running Mosquitto, MySQL and Node-RED as minimal stack on this RPi.  These will all run comfortably on a 2 Gb RPi3.  You won't need USB3 class performance for the SSD either.  It might be worth running a separate Broker on the separate HA system and ping this with a copy of every relay close / open command.  That way you can have an independent watchdog on a separate system to open the relays if the CH+DW RPi dies with the Willis Relays closed.  The last thing that you want is for the UFH to run away, though worst case I suppose the Manifold TMV will isolate the Willises from the UFH loops and the Willis thermostats will cut in, but even so a critical RPi failure could leave you with the slab on.  Bad news. Far better to have an unattended failsafe reset.

 

Edited January 27 by TerryE

[MikeSharp01]

7 hours ago, TerryE said:

The issue is that these use 24V DC coils, so you need to switch 24V DC from your PRi

Yes I agree it's a challenge and I already have a watchdog based, opto isolated and intelligent, interface card for that I designed in 1995 for some work in Petrol Chemicals. So that will deal with safe shut down and I have about 5 spares so they should see me out. I may even update it as it is only 8 channels and is 8 bit based micro (8052) based and has battery backed Ram which could be much better handled today.

 

CONTROLLING the ASHP on / off by soft means is the way I would go for normal operations but as they will still have the standby current I think a controlled mechanical isolation from the mains makes sense. When you don't need it and I guess the choice of UVC, SunAmp and the amount of Solar available will have an effect on how often and how long that will be. If it is software controlled we can even look ahead of the weather and turn it on with enough warm up time when we see demand coming.

[joth]

For the immersion, I was lucky to pickup a

Carlo Gavazzi RJ1P23I50E Semiconductor Contactor 50 A

For about £28 on eBay.

It has 0-10V input which is perfect for controlling from Loxone, no extra hardware needed.

If I didn't have an analogue output spare I'd probably look at a DMX to 0-10V driver, very good prices available on AliExpress.

 

For 24V switching I have a 48channel DMX led driver decoder which has spare channels. These are ideal for driving coupling relays or SSRs.

Home assistant to DMX should be pretty simple and means downstream hardware is fairly cheap and standards based so easy to move to Loxone or kmx or any other system in future if desired.

 

 

 

 

 

[joth]

10 hours ago, TerryE said:

 

Out of interest, am I in the right ballpark for my estimated Loxone costs?  Thanks.

It depends a lot on scope. I've done a few installs now and they all come in at 2-3x what you quoted, even with a degree of mates rates built in, but that's controlling all the lighting, providing the light switches and motion sensors, and perhaps comprehensive shading/stack venting and whole house music, in 5+ bed houses. (In a very expensive area of the country, and I'm expensive too don't you know lol). But that's excluding light fittings, 230V mains work, cable pulling and certs, all done by site sparky.

 

For say just HVAC controls it could be done under £2000 in materials. A retrofit would suggest putting some wireless sensors and controls around the place which is probably tying into their proprietary wireless Air protocol which I've totally avoided to date. I hear it works well, I just dislike wireless.

 

I totally agree the single vendor lock-in is worrisome vs open source, but on the flip side I can leave a miniserver running for 12 months and it looks after itself, whereas with any OSS you need great hygiene on admin work: taking backups and applying security updates (to OS and apps) etc and dealing with the fallout when stuff then breaks. The whole strength is plethora of hardware supported, but it's also the Achilles heal for a (progressional) production system as the more add-ons and integrations you use, the higher the odds (and seemingly exponentially so) that something will break with each update.

I love Home Assistant for tinkering, and providing user specific customisation, but once I have a prototype I try and remove it from the "real" implementation in the fabric of a building. 

 

Fwiw if you can wade through the rambling, there's a bit at the end of this podcast about my thinking on that dividing line

https://www.houseplanninghelp.com/hph334-combining-smart-home-technology-with-energy-efficiency-with-jonathan-dixon/

 

[Temp]

Many relays come in a choice of coil voltage. Can't you find a suitable 5V coil relay and avoid 24V?

Edited January 27 by Temp

[TerryE]

6 hours ago, MikeSharp01 said:

CONTROLLING the ASHP on / off by soft means is the way I would go for normal operations but as they will still have the standby current I think a controlled mechanical isolation from the mains makes sense.

I guess that you'd turn off the ASHP only over the summer, though it might do "maintenance" cycling occasionally.  Long off periods might affect the ASHP life so there is possibly a trade-off between the annualised standby cost savings v.v. ASHP life.

 

One thing that you to do need if you want to optimize energy use for an Agile / ToU tariff is to have a good estimate of the actual heat output of the ASHP.  AFAIK it is quite easy to track the electrical energy consumption but the actual CoP can very quite dramatically depending on load, external temperature and humidity; current ASHPs don't give you this data.  I did consider using an ASHP in without buffer tank but with PHE isolation (rather than a lossless header) as this means that the UFH circuits will be driven with constant head (and therefore flow rate.  This mans the the heat input to the slab is directly proportional to the delta T between the out and return temperatures a measured at the manifold.  However all my ASHP plans have been put on hold because the ToU electricity pricing has dropped my electricity costs for heating by about 50% so installing an ASHP just isn't cost effective for me.  

[TerryE]

4 hours ago, joth said:

I love Home Assistant for tinkering, and providing user specific customisation, but once I have a prototype I try and remove it from the "real" implementation in the fabric of a building. 

 

HA is flexible, easy to customise and the SW + addons are constantly evolving.  Another way of saying this is that it is a bit fragile and upgrades sometime break stuff which is why I have split out my CH+DHW control system onto a minimal Raspbian server booting off an overlayFS and just running Node-RED + MariaDB, for HA.  And even with HA, I run that as Proxmox VM so that Proxmox snapshots, backup and restore are available to do fast recovery if an HA upgrade fails.  I also run Node-RED, MariaDB, Mosquito and Zigbee2MQTT in their own LXC separate from the HA VM so that my Zigbee sequencing is not dependent on HA being up.

[TerryE]

4 hours ago, Temp said:

Many relays come in a choice of coil voltage. Can't you find a suitable 5V coil relay and avoid 24V?

 

Possibly as there no technical reason why you couldn't, but the issue here is volume demand and product availability.  Industrial control systems typically use 240VAC or 24VDC so that's what the relay manufacturers target -- at least in the UK -- so it's quite hard to find DIN mounted relays with 5V coils that are rated at 240 VAC / 3000 VA AC1.

 

Most modern micros only drive 3.3V GPIOs, so you still need some form of add-on board to drive 5V.  Again because 24V is a de facto standard a lot of add-on boards can drive 24V.

 

For my existing implementation, I did my own prototype based boards which used ESP8266s and custom logic to drive my SSRs at 5V.  I want to retire these and switch to COTS boards which support an OS firmware build of something like Tasmota.

 

Edited January 27 by TerryE

[ProDave]

26 minutes ago, TerryE said:

Most modern micros only drive 3.3V GPIOs, so you still need some form of add-on board to drive 5V.  Again because 24V is a de facto standard a lot of add-on boards can drive 24V.

I just used a simple emitter follower to connect an I/O pin of the Arduino to a 5V solid state relay.

[joth]

1 hour ago, TerryE said:

8 hours ago, MikeSharp01 said:

CONTROLLING the ASHP on / off by soft means is the way I would go for normal operations but as they will still have the standby current I think a controlled mechanical isolation from the mains makes sense.

I guess that you'd turn off the ASHP only over the summer, though it might do "maintenance" cycling occasionally.  Long off periods might affect the ASHP life so there is possibly a trade-off between the annualised standby cost savings v.v. ASHP life.

 

For better or worse I'm not using glycol so I have to be very sure the thing is powered up whenever it is liable to freeze. (which is similar times of day and yar to when I want to use it for heating most, mind you)

I also use if for DHW so need it powered up at least once a day for UVC reheat. 

And my control logic isn't yet clever enough to know I'll need to use it in ~1 hour, so I'd need another layer of prediction to power it up and let the crankcase heater do its work before calling for heat.

 

I now have the ecodan modbus interface so have fairly fine-grained control over it. It does include a system power off/on function. I'm wondering if that saves on the crankcase heater when still keeping the freeze-stat function. I will experiment at some point, but it'll only be for course savings; it still needs that  level of predictive control I just don't have built at this point. (Like, predicting someone is about to run a bath and two showers and empty the UVC at an unusual time of day - it's actually a  tough problem).

 

Edited January 27 by joth

[Alan Ambrose]

Ah you've hit upon the big problem with current home automation:

 

either cobbled-together home grown systems which probably only you understand (and what will the next owner do) and which probably have reliability and maybe safety problems,

 

or off-the-shelf (Loxone etc) vendor systems complete with lock-in / internet & vendor server dependence / limitations as what feature are covered.

 

I plan to borrow what I can from grown-up office building automation systems (think big office buildings, KNX etc) and custom wired but upgradable industrial control systems (proper automation cabinets etc). All fairly properly documented.

 

I figure the key thing is to get the wiring flexible and well thought out mostly back to central cabinets / then a fairly well built automation cabinet or two / then whatever software you need. The software - preferably you set it up and then leave it alone rather than tinker with it constantly. The software / automation engine can then fairly easily be switched out at a later date if necessary or as and when some new technology appears.

 

I think consumer-grade is largely a waste of time and energy due to short lifetime / missing support / safety / fragility / security - although I do have cheap and cheerful consumer grade in my current place for the odd thing (e.g. switching outside lights based on dawn/dusk timing). Fine for experiment and 'user experience' testing, but there's always the 'will my wife ever learn to run this?' / 'what will I do when I sell the place?' questions.

 

So no great answers atm, but maybe a strategy of 'enabling' a building with wiring and switching along with 'whatever works now' software - until a proper standard and some competitive substitutable offerings come along. The risk is that a technology appears that would really benefit from rewiring - but I figure plenty of network / mains / low voltage cable should take care of that.

[TerryE]

@Alan Ambrose A good summary, but I also fear that vendor lock-in has a whole range of risks in its own right, especially if the product is using vendor proprietary closed-source applications and firmware. It's over 40 years since I started my career in IT and in that time I've seen dozens of vendors and "best-in-class" product ranges fail and get withdrawn from the market.

 

In my case my test is "what happens if I die or lose my marbles".  In my case my elder son and son-in-law both work in IT and automate their own homes using pretty much the same technologies, so could step in or at least provide a soft landing in extremis.  Even so, that's why I have split my stuff into two categories:

• The consumer grade IoT goodies that I control by HA.  These are "nice-to-have"s, but if Jan wanted then she could bin the whole lot without impacting her life too much,, as nothing here is critical to lifestyle.
   
• The CH and DHW systems.  In a sense these are "mission critical", in that life would be grim if they failed even for a few days.  It is here that I want to explore if there is a practical and realisable mid-ground; one that could be supported by my sons if needed.

Apart from issues of modularity and safety, this is why I suggest splitting out the 240V stuff from the control which should be implemented at 24 VDC or less.  The 240V circuit switching should be done by DIN rail mounted devices with the RoHS and BS certification for this use -- something that a typical Part P qualified sparky would be comfortable fitting and signing off.  In terms of the "next owner / electrician" such DIN mounted switching devices are simple field-replaceable components, if the owner wishes.

 

In terms of the 24VDC control for these relays, I want a COTS unit that can simply be replaced by a functional equivalent,  if necessary.  The other thing that is a bit of non-no for me is using a device that has its own closed source firmware, especially if it is "cloud-enabled".  I agree with Mike that the Shelly Pro 4PM is a really interesting product but I have real concerns about it's closed-source firmware. That's why I currently prefer the Sonoff equivalent which another ESP32-based device but is Tasmota firmware compatible.

 

In 5 or 10 years either could be simply switched out by whatever the current flavor of device is leading the pack. 

Edited January 27 by TerryE

[Temp]

3 hours ago, TerryE said:

Industrial control systems typically use 240VAC

 

One possibility might be to use a small SSR to switch the coil of a relay that has a 230VAC coil. No DC power needed at the relay. SSR gives you the isolation.

 

Main problem with ideas like this is that it's a home brew solution an electrician might hesitate to use.

[joth]

2 hours ago, Alan Ambrose said:

Ah you've hit upon the big problem with current home automation:

 

either cobbled-together home grown systems which probably only you understand (and what will the next owner do) and which probably have reliability and maybe safety problems,

 

or off-the-shelf (Loxone etc) vendor systems complete with lock-in / internet & vendor server dependence / limitations as what feature are covered.

 

I would add to these:

 

or it's an established domain specific standard with multivendor support, but designed multiple decades ago, antiquated and a pain to use e.g. KNX.

 

or it is Matter, which is of course trying to be the one-new-standard to solve them all, but I see several issues with it, mostly: wireless focused no standardized wired support; slow development; only has limited device types/profiles and not a great playground for vendors to innovate new device types. So all in all not a good choice for integrating into the fabric of a new build, not now, maybe not ever.

 

If https://www.1home.io/server-for-knx really works and gets traction, it could form the bridge between the incumbent wired KNX and new kid consumer friendly Matter, and perhaps be the best path forward, but it's early days.

 

[TerryE]

31 minutes ago, joth said:

or it's an established domain specific standard with multivendor support

 

MQTT ?

[joth]

17 minutes ago, TerryE said:

 

MQTT ?

Modbus even more so. Maybe DMX and Dali, a few others.

 

MQTT is stuck between camps. Unlike KNX etc it's not a complete standard, just an application layer protocol. (A bit like modbusTCP or KNX/IP).  It depends on a lot of other stuff to work, ethernet and IP layer,  stable device naming or addressing, and good luck if you want TLS encryption.

I certainly wouldn't want to build core house functions like lighting and heating around it. But nor is it consumer friendly either, it takes so much manual config.

It shocks me to hear myself say this as MQTT support is one key feature I find shocking to be missing from Loxone, but maybe I just answered it 😂.  Loxberry is moving to use it as the core messaging fabric. Maybe things will keep moving that way.