What's your HA reliable architecture ? Mesh + central controller?

Setup, Configuration and Use Beginners
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It is worth noting that this is probably the wrong approach. You will get better redundancy, or robustness, by using a single system - yes, that does open you up to a systematic failure (eg if ZWave had a major problem then your system would go down) but if you use technology like ZWave or ZigBee that have been around for many years, such a systematic failure is unlikely.

Also, I guess redundancy isn’t really what you have, as you probably don’t have every light using both ZWave and WiFi such that if one system failed, you can still switch a light with the other?

The point though is that if you use more devices in a mesh network, you will have a more reliable system - the mesh will be better, the controller will have more options for routing, and overall reliability will be better. By using multiple systems, you potentially significantly reduce the robustness of your system.

WiFi has many issues in this space…

Currently, most WiFi systems are not mesh networks but are point to point connections.

You must ensure that you have a system that can handle enough devices. Most low cost WiFi systems that most people have at home do not support the number of connections required for a “full house” home automation system where every device is on the network.

WiFi will typically not work well for battery devices - ZigBee/ZWave mesh systems are designed with super low power mesh networking in mind.

Also note that there are currently limited application standards over WiFi, so devices can’t talk to each other (unless they are the same manufacturer, but then you’re back to the systematic failure issue).

ZigBee/ZWave all have well defined application layer interfaces to allow devices to communicate and interoperate. You know that if you buy a certified device in one of these systems, it will talk to other devices - even from different manufacturers (in at least 99% of cases anyway :slight_smile: ). WiFi is just a transport layer, so you need something on top of this to provide the application - possibly MQTT is becoming more common that it might one day meet this need - who knows.

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I mostly agree with that @chris said. Mesh seem to me the best way, to an efficiency and low power point of view, and reliability point of view. For a simple smart house, Wifi could be a simpler solution, but if you want to add door sensors, light sensors, temp sensors and so many things, you will reach limits pretty fast.
It is not my case right now, but I love to create DIY things like sensors, and I don’t want to restrain my possibilities at start.
I should add a mesh communication protocol along my central controller.

To do that, the difficulty is that Zigbee and Zwave are not DIY-friendly. Creating a custom module and firmware to design my own sensors and nodes are not really easy, and not well documented.
I am currently searching in BLE mesh (HM-10 BLE + Arduino) or RF mesh (nrf24L01 + Arduino) that seems to be more documented.

If anyone has another advices on those subjects, you are welcome :wink:

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ZigBee is very well documented, and there are many suppliers of hardware who have their own documentation for their frameworks, so it’s not so hard (although it’s also quite a complicated protocol in some ways).

ZWave is also well documented, but there is of course only a single supplier of devices, and IMHO the Silabs documentation here (which to be fair they inherited recently from Sigma!) is not good, so it’s definitely much harder to play in this space.

IIRC, BLE-Mesh is not a real mesh, but uses broadcasting rather than routing. This will have some limitations.

From my experience, BLE and ZigBee probably have similar “DIY learning curves” - it depends on the devkits and tools etc that the chip manufacturer supplies. My recommendation would be to go for ZigBee - the other problem you will have with BLE is you will need to be responsible for both ends - ie the device, and the binding since there are limited application layers available for BLE (AFAIK anyway). If you implement to the ZCL, then you have compatibility with the ZigBee binding, or the zigbee2mqtt etc binding.

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Thanks @chris for those precious advices.

For you, what would be good modules to go DIY and start in Zigbee ?

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I agree with you that WIFI might be problematic in case you have many nodes. I have multiple acces points which are capable of more than 100 clients, so I do not face any problems.

It ls also obvious that using 2 technologies is real redundancy (that’s why I mentions ‘kind of redundancy’) at least the lighting in the house divided, so if one of the 2 infrastructures is down, there is no need to stay in the dark.

From low power point of view Zwave and/or Zigbee are definately more capable than WIFI.

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Not sure if it satisfies your definition of mesh, but the MySensors project is basically this: super cheap nrf24 radios attached to super cheap arduino clone boards, perfect for battery powered operation.

I’m basically an idiot when it comes to software and programming, but even I’ve managed to get a DHT22 sensor up and running and communicating through the MQTT Gateway with openHAB.

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I’d keep it simple… Z-wave dimmers such as fibaro/aeotec/qubino.

If you in the uk and don’t have a neutral - no problem - find the light that has the switched live present and wire it in above the fitting.

It will physically work with the existing switch even if your system failed.

Out of all my devices, Zwave is by far the most reliable and wish I could get everything in its format.

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Thanks for your advices all.
But I would like to stay with a DIY compatible protocol, to be able to add custom sensors in the mesh network (I would probably mainly go with custom sensors and nodes). And for what I know, Z-wave board modules are not easy to find, and not the cheap.
Zigbee board modules seems to be simpler to find and cheaper.
I still need to find the good one…

I will take a look at the MySensors project too.

Edit : MySensors is star network and not mesh network. It’s not as reliable as a mesh network like zigbee or assimilated.

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That one does it too. I think there is an internal relay triggered either by the local physical switch or through Z-Wave,

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Assuming we’re using the Wikipedia definition:

In a star network, every host is connected to a central hub.

Then this is both true and false for MySensors, depending on your interpretation. As described on the pages I linked in the previous post:

  • MySensors nodes can act as repeaters for other nodes, and that topology is dynamic - i.e. you can move nodes around and the network will automatically update, just like Z-Wave and Zigbee.
  • By default all data comes back to a central controller, just like with Z-Wave and Zigbee. However, you can directly associate non-controller nodes with each other, bypassing the controller directly - just like Z-Wave and Zigbee.

Certainly, using MySensors is more of a faff, and probably not as robust as Z-Wave and Zigbee by virtue of its DIY nature. I would personally love to be able to make DIY Zigbee modules, but the off-the-shelf prototyping boards cost an order of magnitude more than a MySensors build. I did come across a project which used IKEA Tradfri products, and just pulled them apart and used the boards for DIY projects but my Google search skills are failing me.

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I personally use Silabs chips - it’s what I know, and they have good software etc, although I think you need to buy a devkit to activate it (but I think they aren’t very expensive). I’m sure NXP and TI have similarly good devices and tools.

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Ok, I think we have a different definition of redundancy. For me, a redundant system provides the same functionality through two mechanisms - so you would duplicate all your lights? I guess this isn’t what you’re doing - but instead you have some lights that are one technology, and a different set that are a different technology?

Anyway, this sort of thing is personal, and whatever works for you is of course best :+1:.

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The boards are around $35 direct from silicon labs. You’d need to buy the dev kit though which is about $379.

Also, with the vast amount of Zwave products out there I don’t see the need to make yourself when you have things such as fibaro’ smart implant for sensors / digital inputs and a whole host of relays and switches. The only real thing missing from the uk market is actual ‘sockets’ (not plugs).

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Sorry, are you talk about specifically wireless system? I have a knx ecosystem and I think it is expensive but it don’t have single point of failure except for the openhab. Actually with KNX you don’t have physical dongle or other particular stuff, so I think it should be possible to do a redoundant configuration whit 2 raspberry and a simple script

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Ok I haven’t seen that, that nodes can communicate without pass by the central controller. I will look deeper in this way. But what if a node need to communicate with one other node, passing by an intermediate ? In other words, can MySensors be used to realize a real mesh network or does it have limitations ?

Thanks, i will look at TI CC2530. It seems to be largely diffused, and some’s custom firmware for Zigbee 3.0 have been released :
TI Z-stack
Zigbee 3.0 custom firmware zith GUI
Zigbee 3.0 custom firmware
It could be a good starting point.

Yes, it what I have said. It is not cheap. If you want to design and implement multiple sensors and actuators on your house, it can be expensive. At this price, it seems better to go with existing devices.

You don’t see the need, but I see differently.
• Fibaro devices, and Zwave generally, are expensive. The smallest Fibaro dimmers reach easily 40-50€. If you want to implement a lot of sensors and actuators, it can be easily out of budget.
• Using existing devices is an easy way to reach the goal (add automation in house), but is limiting in some way. If you want to add, for example, light + temp + humidity + door contact, you can do that the DIY way on only one node. If you go with existing devices, you must buy light node, temp+hum node, and door contact node. And some sensors not exist or are very expensive (VOC or gas for example).
• Going the DIY way permit learning and develop some knowledge. It is a hobby.
I am not telling what you said is a wrong. If you don’t want to spend a lot of time to develop things and you have some money, it is probably a good way. But I just want to make by myself and learn about a new wireless protocol (I haven’t done mesh network yet).

KNX is a must yes. I have learned it at school at his beginning. If I could build a new house or if I remake all my electric system, I will probably go with it.

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I don’t know what boards you mean, but this sounds expensive. I’d expect about 1/2 or 1/4 of the price - 10 to 15 dollars depending on exactly what you’re doing. Certainly modules I’ve been using are well below 10 British Pounds.

You can spend a lot on starter kits for sure, but I think the basic kit is probably below $100 - and similar to other manufacturers such as TI and NXP.

Sure - there are plenty of ZigBe devices available to do most things, but people always like to make things - as we see in this discussion.

I had to support the 2531 a while back, and TI told me they were not supporting this any more. Really I’d suggest not to go down that route, but of course it’s up to you.

Well, it’s not expensive if you know what you’re doing. You can get PCBs made from China for a few $$$ - very cheap. Then the Silabs modules are reasonably cheap - not super low cost, but you could put everything together with a custom module for less than £20. To me, that’s pretty cheap, but I guess everyone has a different view on what cheap means :slight_smile:

Below is one example of a simple to use Silabs module - just add your own sensors and power -:

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I use a lot of Silabs stuff for the commercial ZigBee work and in general I’d recommend it. As another example I had these dongles made in China and delivered - all up it cost about £120 for 5 units - not super duper cheap, but still not bad given all I had to do was send off the list of parts and board layout to China, and a couple of weeks later these arrived in the post…

image

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Thanks for this precious information, it will allow me not to go on a siding.

Yes it is what I want to make.
That’s pretty cheap, sufficiently to do some experiments, and later to be implemented in the entire house scale.
I will look at the MGM12P02F1024GA-v4 and his devkit. Thanks again :wink:
Edit : It appears that purchase the 499$ devkit is mandatory to use Silicons Labs EmberZnet stack (zigbee stack) and develop zigbee devices with Silicon labs modules. Too bad =/

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I’m a little surprised that the starter kit does not provide the same access to the tools to be honest. The starter kit is $100 as I said earlier.

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If I look at this, it clearly states it “provides all the tools to develop IoT applications” - why do you think the more expensive kit is required?

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You don‘t need a mesh network to eliminate single point of failure. In a system with central controller you can easily add redundancy by adding backup controller in cold backup. E.g you just need a couple of Wi-Fi or Z-wave relays. Changeover will take maximum few mins until your controller boots up.

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Yes it seems that I was wrong. Only kits that are on this page give access to the EmberZnet stack, and the SLWSTK6021A is listed in :

I think i will give it a try.

Yes, but it is more a backup solution, or cold strategy. It is not adding reliability but fast hardware replacement.
It can be a good compromise between mesh network cost (time developement) and no solution.
One other could be a peer-to-peer network. Like MySensors seems to be able to. This way, there is no central broker or gateway that create single point of failure.
In fact, it is the minimum needed. In comparison with peer-to-peer network, and in case that each node can talk with each other without a relay node, mesh network is not adding reliability but just range. But in case some nodes are to far to be able to communicate and a third node is needed to relay message, it add reliability.
At least like i think the things.