Indeed, I also assumed outdoors due to the ranges involved.
Thanks for your thoughts!
Just to clarify the situation: wifi router / hub is placed inside the house. Motion sensors and lights are places outside in the yard / garden.
It was not a bad idea running low voltage cables to the sensors, but for several reasons it would not be practical to burry cables in the location.
PoE was mentioned, what is that?
Several of you mention Zigbee or Zwave. Do you think that it would be possible due to the distance? The signal has to run 30 - 40m from hub inside through walls and then to the devices.
If I set up a repeater device (can devices used as repeaters be run off battery?) just outside my front door, then it would still be roughly 20m from that repeater to the sensor far most out.
I looked at the IKEA Tradfri, which supposedly run on Zigbee, but they declare a distance of max 10m between devices, and I would need far more than that.
Power over Ethernet. Requires cable so not an option for you.
Should be fine. What are the walls made of? My house is double brick and they work well. Property is 1001m2 with devices all over the place.
I think they are playing it safe with the estimates…worst case scenario you put a repeater near by somehow closer than the 20m you mentioned.
Thanks for the reply!
Can battery powered zwave / zigbee devices act as repeaters (and or do repeaters need a wired power supply to not be drained instantly)?
And one additional question - is there an easy way to test if the range is good enough? Maybe buying two zigbee products to see if they respond (but guess I would also need a hub). Any good way to do this without investing too much in a framework that may not work with the range?
Battery powered devices are not repeaters, so you’ll need to find a place to plug in a mains powered device somewhere.
I guess the minimum is a hub and one device, still an investment. Next week I can do a range test for you if you like, but it’s not an exact science as our houses are very different.
Thanks a lot, that is really kind of you!
If possible that would be really great. I know it is not exact since, but it would give some kind of indication whether it would work.
My house is 10 cm AAC, 7,5 cm rockwool, 11 cm brick as shown in this picture.
The hub will be placed inside, and the sensors and lights outside.
FWIW, I did some range testing here at my house last year when trying out my first zwave motion sensor (a Fibaro FGMS001, that sensor has a bultin range testing feature). The limit of signal loss was at about 25m from the Aeotec Z Stick controller (no repeaters). There was a 90cm thick natural granite wall in the signal path, the rest was direct line of sight, the controller stick was about 3m above ground. When I changed the angle somewhat, so that a second granite wall got into the signal path, range would drop to around 15m. I ended up digging a ditch and laying Ethernet cable for better reliability.
Your wall is much lighter and less dense. It should absorb less signal. Also keep in mind that high moisture conditions (fog, rain) tend to increase absorption and signal scattering rates in air and may reduce range significantly. Zwave is a little less prone to that than Wifi or Zigbee, due to the lower frequency.
Thanks a lot for the input and sharing your experience.
I think a range of 25m is pretty impressive if first going through a granite wall. You mention that the controller was set 3m above ground. Does this give better signal spread? I was just planning on placing mine beside my wifi router at table level in the room.
My wall is less dense, yes, but the signal has to pass through two additional inside walls of 10 cm thick AAC. I do not know how much this will impact the signal.
Good point about the weather impact. That would need to be taken into consideration for the system reliability.
As I understand Zigbee runs on the same freq as wifi. I don’t know how much of a difference that higher freq will mean in practice compared to Zwave. But, if I have wifi connectivity to the wifi router in all places where I plan on setting up battery powered motion sensors, will that in theory mean that I will also have zigbee connectivity in those places? Or will a zigbee stick connected to an RPI have a lot less signal strength compared to a wifi router? Also I do not know if there is difference in battery powered zigbee devices signal strength? Can one device/brand have a less range than another or does the zigbee standard ensure that it is the same?
It depends on the antenna type and frequency, there are physical reasons why higher antennas have better signal propagation properties (ground plane reflections, 2nd order lobes for dipoles, etc). But this is more relevant for higher power long range propagation (like radio or cell phone towers, for example). For our type of use, the most important thing is to get as little dense or conductive material into the signal path as possible. Higher up antennas will usually make for a more direct line of sight with less stuff in between, like vegetation, parked cars, people. But that depends a lot on your specific setup of course.
Probably not that much, unless there’s lots of metal in the walls (drywall studs or plumbing for example). Some type of thermal insulation have an aluminum foil on one side, those are deadly for RF signals.
Physically, the difference is very significant. Water absorption (water vapor in the air, human bodies, humidity in walls, etc) is about 4 times higher for 2.4GHz than for the frequency used in zwave (around 850-900 MHz, depending on country). There is a reason microwave ovens work well at 2.4GHz This is usually compensated by higher transmit power, different and more error tolerant modulation, more sensitive receivers and more advanced antenna design and signal shaping techniques (like MIMO). My super thick granite walls are real wifi killers. A wifi signal with a transmit power of +19dBm will barely go through one of these walls. But a zwave signal at -5dBm (that’s 260 times less power !) will go through it without issues. Zigbee is probably somewhere in between. While it shares absorption rates with wifi, it is much lower bandwidth. But again, this is super dependent on your specific setup, construction materials, etc. In the end, only testing can tell.
Not necessarily, as tx power will be very different. A good wifi AP will have around 200mW (or more depending on local regulations), while a Zigbee or zwave stick will have around 10mW. A battery powered sensor will usually transmit in the sub-1mW range to conserve battery. Antenna design can also differ. But wifi and Zigbee are not really directly comparable, because of the different modulations, bandwidth and error corrections. So Zigbee will work at longer ranges than wifi at comparable tx power.
That said, you say you have adequate wifi coverage at the sensor locations. Maybe wifi based sensors could be an alternative.
If you decide to go with Zigbee or zwave, is there a possibility to plug in a repeater node somewhere ? Maybe in a dry compartment or along a wall ?
Thanks again for a very informative reply!
Regarding the placement, I was planning on running a RPI with a Zigbee USB dongle (if Zigbee will be useable in this case). I guess it would be possible to run a long USB extension cable and put the dongle up high, but would that make any sense? Or do you think a dongle will be too weak a signal compared to a dedicated hub?
I have also seen someone mention a USB stick that supports both Zigbee and Zwave, wonder if that would be a good way to future-proof the system?
I do not thing that wifi will be an option because I will need some of the sensors to be run on battery. From what I can read, wifi will kill the battery in a very short time (also I’m a bit paranoid about wifi device privacy issues). On the contrary, I have read that Wifi 6 is coming, but I do not know if that new standard will make battery wifi devices a realistic alternative or if there are yet any devices available to suit it. I guess you will also need a dedicated wifi router to support it.
Below I have included a picture of how I imagine the system. There are actually quite a few places with wired power that could maybe be used as repeater nodes. Can all zigbee devies act as repeaters or do you need specific devices for that? It is easy to configure a device as a repeater, is it done in HA or on the device?
Is it possible to buy a zigbee device that has much lower range than another (so that you have to be careful what to buy)? If yes, what to look for to tell ‘good’ from ‘bad’ devices?
By the way, about the picture and placement of the RPI that will act as the Zigbee hub - does it actually have to be close to the existing wifi router? I suppose that the RPI will not be dependent on the existing wifi router in any way?
Alright, your image is pretty clear. From my gut feeling, that should work fine and you should not encounter any major issues. These distances are within the typical operation range of both Zigbee and ZWave. But RF signals can sometimes be unpredictable and very dependent on the local area and topography. Number 4 might be a little problematic and might require a repeater.
That said, in the absence of any repeater, the signal is not going to travel from one sensor to the next. Each sensor will talk to the controller stick or hub directly. So you have to look at the distances between every Zigbee or zwave device (2, 3, 4) and the hub (1). And you have to think in three dimensions here.
Do this: go to each location where you intend to put a wireless device. Now imagine a virtual line going from the device to your hub or stick, like if you had a laser pointer shining into this direction. You can imagine the hub or stick being at varying heights. Is there anything in the way ? Walls, maybe parked cars, a tree. If you’re on the northern hemisphere and it’s winter right now, keep in mind that what can look like a clear line of sight now, can become much more problematic in the summer when vegetation gets dense. Leaves will absorb signal, especially in the GHz range. So try to find a good position for the stick or hub with the least distance and the least amount of stuff in the way of the signal from the sensors.
Sure, that can be a good option if you intend to use both systems. Some people report those sticks to work less well than ones dedicated to a specific protocol though. Something to keep in mind.
Understood. I don’t know enough about Wifi 6 to comment on it.
Typically any Zigbee or ZWave device that is connected to mains power will act as a repeater. That is automatic and does not have to be configured. But as always, there is the odd exception. So if you have a specific device in mind, you should probably do some quick research (or ask) if it can act as a repeater or not.
Unfortunately yes. Different devices will have different transmit power, different antennas, etc. Zigbee is more problematic than ZWave. The latter is a controlled standard with a tight certification process (that’s why it’s more expensive), so devices will have well defined technical specifications that you can look up and compare (look for tx power and receiver sensitivity). Zigbee is pretty much free for all, and you will find all kinds of implementations for it. Ranging from excellent quality to complete crap bordering on unusable. Usually you get what you pay for. Don’t expect some cheapo stuff from AliExpress to use high quality components.
No, it’s not dependent on the wifi. I assume you have the Pi connected to your network by wired Ethernet ? If you go with Zigbee, it could make sense to keep some distance between the Zigbee stick and your router, let’s say a meter at least, to reduce problems with interference. Also choose wifi and Zigbee channels so that they don’t overlap.
Thanks again for sharing your inputs!
OK, is what you mean that the distances will probably not be a problem even without a repeater - and if so, it would probably work well with repeaters aka devices with wired power to them?
Good guide for thought of placement and good point about the vegetation. I did not imagine that vegetation could invoke much in the signal, but I will definitely have to take that into account as there is a big tree with low hanging leaves in the middle of the path - and, winter here, so no leaves right now.
It would be possible to move the rpi to a more central place if it does not need to be connected to the wifi router with a cable - close to point 2. As I understood, the rpi will act as the brain of the system and does only need a connection to the existing wifi router if I will need to get it online - or does it also need to be connected to wifi router if I will need access to the HA control panel?
I guess the next step would be to get a RPI, a Zigbee stick, a Zigbee battery motion sensor and a Zigbee wired device that can act as a repeater, i.e. a light bulb, and then do some range testing on my specific setup. Anything else good to have on hand?
Is it appropriate to ask for recommendations for devices and a stick with a good range / antenna?
I do not yet know much about good or bad brands in this new world, but it would be to test out the concept, so price is also a factor. Also, if my setup would work without the absolutely best devices (aka a little cheaper build but also a little cheaper price) I guess that there would be no point in getting the most top notch devices.
If deciding that a wifi device would be a good choice for some locations with wired power, would it then be possible to both run zigbee and wifi devices on the rpi and use the same HA instance and brain to manage it all as one complete system? Would that require the rpi to be connected to the wifi router or can the rpi handle it all?
In terms of wifi devices, is there any privacy issues if the iot system is run locally on a RPI with HA?
The best way forward is to have your RPi connected via Ethernet. Is there no way you can move your wifi or RPi more central?
Perhaps look at a proper network system rather than the regular domestic grade stuff most people have. I use Ubiquti gear with 2 long range AP’s. Excellent coverage right out onto the street from my 1001m2 property. Privacy is not an issue, you can setup VLAN’s to segregate things and restrict access where required. ‘The Hookup’ on YouTube has a great 3 part series of how to get it all setup.
For Z-Wave I use an Aeotec Gen 5 Z-Stick and it’s brilliant. Very reliable and great range.
You’ll have to interact with HA in some way, if only for configuration. So typically it will be connected to a network. You can then access HA and its user interface from your PC or a tablet, for example. That does not necessarily means that it would have internet access, if you’re worried about privacy.
I personally don’t use any Zigbee devices, so I can’t help you with specific brands. I’m sure others can though. I also use the Aeotec Gen5 Z Stick for my zwave network, it’s an excellent little device.
I’m not sure I really understand what you mean. If you want your Pi / HA to manage a wifi device, then it has to be connected to some network it can use to reach said device. That can be done by connecting your Pi directly to the wifi network itself using the Pi’s builtin wifi or by plugin an Ethernet cable from the Pi into your router. The latter is usually a better approach. How does you current network infrastructure look like ? Is it just a single wifi router from your ISP and everything connects to that over wifi ? Or is it more complex setup with one or more network switches and some wired connections ? HA itself can certainly manage both Zigbee and wifi devices in an integrated way, as long as it can access them in some way.
Not if you put them on a dedicated wifi network or on a VLAN. Either of which is highly recommended if you use wifi based IoT devices - so you don’t end up with some kid on the other side of the world having fun playing around with your house, or worse, become an involuntary Darknet traffic relay or part of a botnet…
Thanks for the reply!
I can move the RPI to a more central location. I have wifi coverage at most of the property. So if the RPI can be connected with wifi to the wifi router - if that is needed - then it is no problem.
Thanks for the link.
Hi Alex - thanks again the the reply!
Regarding usb sticks I have researched a little. I have come to the following understanding, can you confirm if it is correct?
- To facilitate communication between the zigbee usb stick and Home Assistant you will need to use a software add-on. For example Zigbee2mqtt, deCONZ or ZHA.
- Different sticks are supported by the different software add-ons. So you will first need to chose which software add-on you like and then choose a stick that supports that add-on.
- Zigbee devices are added through the software add-on and not through HA. HA is then used to organize it all into a common dashboard and to make automations and scenes.
Regarding the range; if I chose a zigbee usb stick with a long range it can reach many devices and talk to them. But is that enough for the device to talk back to the RPI? Would the device also need to be equally long range to be able to talk back? What I am trying to say is that it is not enough to have a long range stick if the devices do not have equally long range, then you would need repeaters to bring the message back from the device to the RPI?
If that is the case, then I guess the range of the stick is not very important if repeaters are needed anyway?
Regarding wifi, I was just curious if the RPI could handle both wifi and zigbee connections, of if it would need to be connected to a external wifi router. If there is build in wifi in the RPI, would it then need the external router?
My current setup is just a single wifi router from my ISP and everything connects to that (I have no IOT devices yet, just computers and phones that access the internet through the wifi router).
Regarding privacy I would definately not have anyone else going into the system. I will have to look more into that. But to start, could I just setup the RPI, connect it to my current wifi network through wifi/ethernet cable and then acces HA through a phone or computer without connecting the RPI to the internet (if I just want to be able to acces it locally when home and connected to my wifi)?
I’m afraid I can’t help here, as I don’t use Zigbee myself. As far as I know, the most common sticks are supported by all three mentioned addons.
I don’t know how they’re added specifically, but the second part is correct. HA will act as the central entity that organizes everything and presents it to you over its user interface / dashboard.
Yes and no. All mesh protocols (both ZigBee and ZWave are mesh networks) require bidirectional communication. So you’re right that a device needs to be able to talk back to the controller (or the repeater) for this to work.
From a (simplified) technical point of view, range is a function of both transmission power and receiver sensitivity, assuming equal antennas on both sides. A signal doesn’t just stop somewhere, it becomes progressively weaker until it reaches a point where the receiver cannot ‘see’ it anymore in the sea of noise around it (see signal to noise ratio). A good quality controller stick will usually have both a more powerful transmitter (so that far away nodes with not so great receivers can ‘hear’ it) and a high sensitivity receiver (so it can ‘hear’ the signal of a weak battery powered device far away). You can lookup ‘low noise amplifier’, if you’re interested in more details. So there can be some degree of asymmetry here. But this will only go that far. You are perfectly right that if you have a very weak or low quality device, then the stick might not be able to see its return signal, even if it can reach it. In that case, you’ll need a repeater. Only testing can tell.
Yes, the Pi has onboard wifi. You can use this for connecting to your router. Both wifi and ZigBee (over the controller stick) are handled simultaneously by the Pi. Typically people will suggest connecting it to your router using a cable, because it’s more stable and a dedicated wifi router will have a much better range than the Pi. But nothing stops you from just using the onboard wifi to get started.
Yes, that’s perfectly possible. Just make sure to block the port in the router, so it isn’t inadvertently open to the internet. Most ISP delivered routers will do this automatically (incoming connections are usually blocked by default).
Once again, thank you for very informative answers!
I think I have soon understood the bare basics
I have been looking at zigbee sticks - the Zigbee2MQTT page lists some compatible sticks, that also seem to compatible with the other software add-ons: https://www.zigbee2mqtt.io/information/supported_adapters.html
From what I can tell, range-wise the CC2538 + CC2592 - Zigbee dongle, the zzh! CC2652R Multiprotocol RF Stick and the CC2652RB development stick might all be good choices for a long-range setup. The latter two seems to be multi-protocol and not just zigbee. But I am a bit unsure if the CC2592 amplifier would be the most powerful option - or if one of the other sticks would be better?
Also I am a bit confused about flashing - I would prefer a stick that does not need additional hardware to flash, as I guess you will eventually need to flash the hardware to provide support for new devices or updates to the zigbee protocol?
Does anybody have some insight into this?
EDIT: Since these questions about a stick qualify for a new discussion I have made a new thread here: Best most powerful zigbee stick?
I still have the same doubt cause i have read on the community web page about bulb repeaters and other usb repeaters. But iam confused which repeater to order for and if i get it then how am i supposed to integrate it us repeaters in the zigbee2mqtt using a usb cc2531 dongle.??