Comment by xoa | Hacker News Reader

Comment by xoa | Hacker News Reader

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I wish there were more sensors and other smart home devices that a offered power over ethernet option vs WiFi/BLE/Zigbee. In many spaces running a wire isn't much of an ask, and it particularly is a nice complement to wireless since the spaces it's most trivial to do so (unfinished non-living areas) are also the most irritating to actually get to, have poor wireless coverage, don't have other power available and one wants reliability. PoE also means tying into other infrastructure (like everything can take advantage of a UPS and network power control) and eliminates a whole class of trouble points. Wireless standard support for IOT stuff tends to really, really lag and security is more than a bit questionable. For WiFi a dedicated SSID that is 2.4GHz only, DTIM 1, its own VLAN (or multiple via PPSK or at least PSK+MAC) and with basically every feature added past 2011 turned off helps but some kit still makes me wish for a simple plug particularly when it wants a wall wart anyway.

Ah well. I'm glad there is still a reasonably healthy selection at all for those of us who have the same criteria in terms of "LAN only capable/HA control/no subs".

PoE is a bit excessive for this I think. Most of these IoT devices should be using less that 1mA on average, usually a lot less.

They also need next to no data transmission rate in a lot of cases. 3 or even 2 thin wires could easily handle it.

You could even reuse USB-C as the connector, and optionally actually use the USB lines for configuration, or use barrel jacks for a bit more power and easy DIYing.

If you limited it to just really simple stuff you could use very thin cheap wire, branching however you want because you only need 4800 baud or less, easy to hide, almost no cost.

>PoE is a bit excessive for this I think.

I don't agree, and it's not really about the power (though there are plenty which either are or could be hungrier if the capability was there). Ethernet is very cheap, standard, and reliable. It's easy to run by people who aren't electricians. Ethernet benefits from vast economies of scale and market, you can get minimal Cat 5e for <$0.07/ft (7 cents per foot), and piles of connectors too for pennies. It will be easy to pull and handle plenty of abuse. You can get it riser or plenum rated. Connectors cover a full spectrum of usage and are straight forward to do fast and then test for correctness with a massive array of tools also spanning the price/performance spectrum. Are you for real in suggesting USB-C vs 8P8C?

I'm not suggesting at all using PoE exclusively, but it is disappointing it's as rare as it is in commercial products. There's plenty of devices I'd like to just put somewhere and not touch again for 10 years, which battery isn't ideal for. Security, more stuff broadcasting into limited spectrum, trouble shooting and so on also factors in. It's particularly galling for things which actually do need hardline power anyway, are security/safety related, or both. Wireless absolutely has its place but shouldn't be the only option, particularly when it's commonly so freaking bad (like devices which make things "easy" by demanding to use an app and pair with the network your phone is on rather then just letting you enter an SSID and passwords and then mysteriously won't work arrrrrghhhhhh).

POE has downsides as well though. It's lossier then pulling directly from the wall. It has worse idle power consumption. It requires larger\more expensive electronics on the RX side. You need to be more careful with lightning protection. It's rarer in-walls compared to power lines.

It sure has its strong spots, but it's not a slam dunk for all options.

On the relay side, this is a solved problem. Have a look at devices like the Shelly pro 4pm.

On the sensor side, there are a few very nice esp32 based boards. Have a look at the https://www.olimex.com/Products/IoT/ESP32/ESP32-POE-ISO/ and friends. These kind of things are fairly cheap and will handle most sensors really well. They're also perfectly supported by esphome.

I'm fiddling with a setup somewhat like what you describe at our countryside cottage. Star topology for literally everything into the technical room: 230v power, proper cat6 for the high speed data network, and cat5e for sensors.

I tried to keep the wiring super standard. All sensor cables get terminated centrally in a patch panel, ethernet style. On the sensor side, I break out the wires I want using simple couplers.

I don't do PoE up to the sensor. I haven't found cheap super compact PoE devices . That's not a problem though. With some multiplexing, an ESP32 can handle a surprising number of sensors both at the data and the power budget level. So I use a few PoE powered ESP32's in the central network rack, and I power my sensors through those.

Unifi has a lot of options for this especially if you look at their Early Access store. Home Assistant support is limited right now, but a lot of their devices are still new

I’m disappointed that there aren’t any hubs with PoE or are nice enough to mount on the ceiling next to APs.

Heck, I’m disappointed there’s no ceiling-mount APs with built-in Z-wave/Zigbee.

Would a Raspberry Pi with PoE hat plus USB Z-wave stick (plus USB wifi radio, if you're looking for it to also be a "AP" and want better than out of the box with hostapd) work for you?

Z-wave's relay design makes hub placement less of an issue than with e.g. wifi, which is probably why you don't see much attention paid to mounting/appearance concerns. It doesn't much matter, so long as you have a device near the hub, then another device near that one, and so on.

I do appreciate this suggestion and have considered it in the past. The spouse acceptance factor for mounting a computer board to the ceiling is low in my household. :)

I hadn’t considered that the mesh nature of home control devices has negated the need for central placement.

Ubiquiti has the UAP-IW-HD, in-wall mounted four port POE/wireless AP that uses a standard mounting box. I replaced my old cable TV outlets with them in a couple of rooms and they work great.

Does Ubiquiti’s stuff conform to POE standards these days - for a long while it didn’t

Yes, I'm running my stuff from an Aruba PoE switch; UAP-Lite (the "new" versions with PoE) and U6-lite. Some of the newer devices use PoE+, like the U6-pro.

They have documented this here: https://help.ui.com/hc/en-us/articles/115000263008-UniFi-Sup...

Or the cheaper TP-Link version: TP-Link AX1800 Dual Band Gigabit Wall Plate

I guess by hub I meant home hub device.

I agree and would love to see a list of what is out there, and some elaboration on good microcontrollers / accessories / platforms to use for bespoke projects.

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