POE for my Smartthings Hub

project_power

(Ken Hilbert) #1

Has anyone created or purchased a solution to power their hub via POE? I plan to relocate my hub to more central location and would like to forego to power adapter.


ST & Powerline Ethernet Extender / Adapters
(The fish is still dead.) #2

The ST staff has said there are no plans to support PoE. The power adapter is here to stay. =)


(ActionTiles.com co-founder Terry @ActionTiles; GitHub: @cosmicpuppy) #3

Something like this, but with the right sized plug for Hub V2 (5v 2amp is rating needed, I think)…


(Benji) #4

This is what I plan on using:

http://www.tp-link.com/en/products/details/cat-4794_TL-POE10R.html

If ST V1 needs 5V/2A it should be good, not sure what the V2 is going to use. I already have one of these powering a TP-Link 8port Gigabit switch. I’m about to use more of them to power the following:

Ubiqiuiti USG (router)
Philips Hue Hub
Motorola SB6183 (cable modem)
Raspberry Pi


(Mike) #5

As I’m running out of regular outlets but have a couple available PoE ports I started thinking about this today also. There is a company that sells a PoE adapter which you can break out into various plug types. Here is the splitter:

Then you would use the appropriate adapter to connect:

I’d like to do this but have no idea which adapter, if any, is appropriate for the ST hub (v2). I wish it still ran off USB like the previous generation - I have loads of USB ports around.


(Benji) #6

I need to put my batteries in my hub as I haven’t done that yet and since it requires me to remove the power and network cable, I’ll do this tomorrow and I’ll try and power it with this PoE adapter which I have:

http://www.tp-link.com/en/products/details/cat-4794_TL-POE10R.html

Last time I checked it was able to output the same specs as the adapter that comes with the ST hub. Power for me comes from a 48 port Ubiquiti PoE switch. I’ll let you know.


(Mike) #7

Please do. It’s not clear to me how that adapter would work without another cable so if you get it working please snap a photo or two and jot down the part numbers of the products you used. There probably aren’t a ton of people doing this but with some cameras allowing for PoE we may see more average consumers with PoE switches.


(Benji) #8

Okay, ST v2 hub powered by PoE, it works :smile:

So I was just going to dump this all in and let you all fend for yourselves but in the interests of you not blowing up your hub I feel I should do a little bit of an explanation. Usual disclaimers apply, this is NOT supported and there are no guarantees it will work at all. I’m NOT responsible for any loss or damage to any property or data. At this point I have openly admitted to ST that I have used a power supply other than the one they give you with the hub and I accept that in all likely hood that if I have any issues with my hub, ST will tell me to go and pound sand and they have every right too. If you choose to attempt this as well you MUST accept this risk.

Firstly there are a couple of ways people do PoE and they are what I will call ‘the proper way’ and ‘faking it’ -

Faking It (PoE):

With this method, people use some sort of device that merely takes whatever power supply you have, and electrically connects it directly to the unused pairs of wires in an Ethernet cable when running at 100Mb.

There is no intelligence going on, no conformity to any legitimate PoE protocols and will inject whatever voltage your power supply has onto those wires. You may find that the voltage will drop by the time you reach the end of the cable if doing long runs and also, if you plug the other end into a device without splitting the power back out, you’ll probably fry whatever is on the other end.

I’m not a fan of doing it this way so I’m not going to go into any detail about it.

The Proper Way:

Welcome to IEEE 802.3af/at, have a read:

Now, at this point there are a couple of ways you can do this properly and it’s all to do with how you are supplying the ‘power’.

The first way is if you have a PoE switch (which is how I am doing it) it’s stupidly simple and I HIGHLY recommend the TP-Link stuff (in either setup) for a couple of reasons:

  1. It’s one of the few that can support Gigabit Ethernet even when using PoE if it’s needed, though if the ST hub starts pushing that kind of throughput I’m going to be asking some questions!

  2. It’s CHEAP. Like, it’s almost certainly cheaper than ones that don’t support Gigabit Ethernet anyway so you might as well get these.

So, if you have a PoE switch that supports 802.3af/at, all you need is a TP-Link TP-POE10R which is the splitter -

It comes with the power cable and an extra Ethernet cable for about $14! How cool is that!

So once you tear that bad boy open, what I want you to do is pay extra extreme attention to the voltage switch on it. You’ll note on the picture I posted above it can support three different output voltages and will list the current it can supply at those different voltages:

  • 12V / 1A
  • 9V / 1A
  • 5V / 2A

So the first thing we need to do is set the correct voltage and how do we do that? Well… what does the power supply say that comes with the ST hub? There are two important bits of information here:

The first being that it outputs 5V and can supply UP to 2A. Can our PoE splitter match that? Yes it can output 5V (so go ahead and switch it to 5V NOW) and it too can supply UP to 2A, remember with current the device draws whatever current it needs from the power supply, not the other way round, so as long as whatever splitter you use can supply 2 amps or more at 5V then you’re okay, if the splitter can only supply say 1A @ 5V then we’d have a problem in this instance and you should not even try.

Voltage on the other hand is ‘supplied’ by the power supply regardless, if you get the voltage switch wrong, it’s highly likely you’ll kill whatever it is you’re plugging it into. Now the second piece of important information is the little diagram on the right, this indicates that the center part is + (positive) and the outer part is - (negative) which must also match what the splitter outputs (and in this case does) otherwise you might kill something again.

Now that we’ve got that out of the way, let’s plug everything in:

  1. Connect the Ethernet cable that ST supplies into the port on splitter that as labelled something like ‘DATA ONLY OUT’ and then into the Ethernet port on the hub.

  2. Next we’ll connect the black power cable that came with the splitter into the ‘POWER ONLY OUT’ from the splitter and into the power in on the ST Hub (you’ve set the voltage to 5V… RIGHT?).

  3. Finally, I plug an Ethernet cable into my switch (all of my ports are PoE, yours may vary) and then the other end into the splitter that is labeled something along the lines of ‘Power+Data IN’.

Before you lot jump on me, yes, I know, it’s a mess… I know I should be ashamed of myself especially since I used to work in a datacenter and now I’m a networking guy… Believe me, there’s a plan, there’s a 12U rack sitting right behind me where I took this picture but we’re currently decorating and the things that are currently ‘needed’ are just thrown together…

Anyway… Green lights!

Now, if you DON’T have a PoE switch but you still for some reason want to power the ST hub via PoE then I would probably say this ‘kit’ is your best bet:

http://www.tp-link.com/en/products/details/cat-4794_TL-POE200.html

It seems to only support 100Mb for some reason, not that’s an issue for the ST hub but most importantly comes with the appropriate 48V power supply to inject PoE properly. If you have your own 48V / 0.5A power supply you can probably just get the injector instead:

http://www.tp-link.com/en/products/details/cat-4794_TL-POE150S.html

And use it with the splitter above. Now, one last time, HAVE YOU SET IT TO 5V? Any questions?


Smartthings V2 UK hub power options
Thanks to the community
HUB Location
ResetPlug for Modem/Router/Hub
(Andy Rawson) #9

@Benji excellent writeup, I have been using those TP-link PoE adapters for my raspberry pi cameras for a while now and they are great.


(Benji) #10

Yep, love them, I use one to power an 8 port switch in the bedroom, I would use one to power the Hue Bridge but it’s a different size plug for the power so need to get an adapter, I now use one to power the ST hub and I have one to power my Raspberry Pi.

The ONLY issue that I know with them is to do with the non-isolated ground. Absolutely fine if you aren’t connecting to a device that is grounded by other means but from what I’ve seen (I’ve not tested myself) if you have another ground it’ll short, for example, you can power a Raspberry Pi just fine by the PoE splitter but if you plug in say an HDMI cable into the Pi, which grounds the Pi to whatever you’re plugging into the other end, you’re going to have a bad day:


(Benji) #11

Okay, just an update, the previous comment I made is extremely critical, you’re not just going to have a bad day, you could potentially destroy your equipment. I’ve been lucky with my little 8 port switch, router and SmartThings hub because they aren’t connected to anything else other than Ethernet!

So why is Ethernet okay and not anything else? Because for the most part all (should be anyway) RJ45 Ethernet ports use galvanic isolution to separate grounds which is what the issue is related too:

Turns out if I had used a PoE splitter on my cable modem for example (and I was just about too!!!) it’s highly likely I would have blown it up since it is grounded via the RG6 cable as well.

So while my ST is currently fine, if I were to ever plug anything in those USB ports that say has its own power supply or connects to something else that does…

You have been warned…


(Chris Fichter) #12

Please don’t take any offense to this but, " faking it" has many good applications. IP camera for example. And for long runs it’s not voltage that drops its amperage. And you won’t blow anything up doing a run that is to long. It just won’t work. More than likely the average house will not have any issue running fake PoE, when it comes to long runs anyway. Unless you live in a mansion. The thing you have to worry about is with what you’re talking about with real PoE is getting the right equipment.


(Benji) #13

No offence taken at all and it’s a valid point however, these days the majority of IP cameras support real PoE anyway and PoE switches are so cheap these days there’s little point in ‘faking it’ any more.

Plus with real PoE you don’t have to worry about voltage drop over long runs.


(Craig Pratt) #14

Thanks for the write-up. Just did this myself and it’s working great so far. But I’ll do a week of burn-in testing.

The only thing I’d add is that you probably want to keep the batteries out of the ST hub if you want to be able to reboot it using the PoE port.


(Benji) #15

Yes good point, although I’ve personally never had to reboot my ST hub, that being said, I still took the batteries out after I realised they had gone flat after the many power cuts we have. Better off with a UPS on the PoE switch than batteries in the hub.


(Martin) #16

Just to add comment here, I’ve been running my ST hub using a PoE Splitter for about a year without any issues. I can’t comment on other challenges other members have experienced but for me its been a good option to reduce cable clutter and remote power points.

Good luck.


(Craig Pratt) #17

I’ve had to reboot mine just once, I believe - maybe twice - but only when the v2 hub was new. It was easy since it was here at home. But as we’re planning on using a second ST hub to manage access to our vacation rental home (adding and removing keypad codes), a manual reboot would be a 3+ hour affair.

What’s great is that the Ubiquiti ToughSwitch has a “Ping watchdog” which can automatically reboot the hub if it fails to ping for a certain duration of time. I’m not going to set that up initially. But I’m sure I will - with probably a very long timeout, just to be safe…


(Craig Pratt) #18

Great to hear - thanks!


(Martin) #19

I have the tough switch too but hadn’t thought to setup the ping watch feature. Will look into that - thanks for sharing.


(Benji) #20

Just be careful with the ToughSwitch and (depending on) your splitter.

If I remember correctly 24/48V “PoE” on the ToughSwitch doesn’t comply with 802.3af/at so just be careful! Don’t want you blowing anything up!