Nah, ESP32's have had ethernet capability for a while and ESP-IDF supports it well. I've been using one I built for 5+ years now. Unfortunately RMII (ethernet phy) interface takes up a lot of the GPIO pins. This part looks like it'll remedy that issue.
There's two ESP32 boards that have been around for a while with PoE:
> I'm more hopeful for single-pair ethernet to gain momentum though!
I keep looking for a reasonably priced 10baseT to 10Base-T1L bridge... everything commercial seems too expensive (for me) and the two hobby designs [1] [2] I've seen are not orderable :(
But I'm seeing more commercial options lately, so that's hopeful.
Multidrop SPE isn't going to outperform newer CAN versions though. Somewhere in the sub-100Mb/s (e.g. 10-20Mb/s range) is the practical maximum speed of a multidrop bus at useful lengths, and that essentially applies equally to CAN or SPE. The only way to really get faster in a "multidrop-like" sense is with logically loop-like systems like ethercat and Fibre Channel where each network segment is point-to-point and the nodes are responsible for the routing.
On that note, why does the PoE capability often add such a big proportion of the price of various items? Is the technology really costly for some reason, or is it just more there's fairly low demand and people are still willing to pay?
PoE is not obvious to implement (take it from someone who has done it with a fair share of mistakes), uses more expensive components that normal ethernet, takes up more space on the board, makes passing emissions certification more complex, and is more prone to mistakes that ruin boards in the future, causing support/warranty issues. In other words, a bag of worms: not impossible to handle, but something you would rather avoid if possible.
I wouldn't call it "better", but the least-effort path among hobbyists and low end gear is often 12v or 24v sent over a pair with Gnd and a forgiving voltage regulator on the other end.
A full-module add-on in this power class is about $7 at 1,000 unit scale [0]. It would be around $3 with your own custom PCB design in terms of BoM addon at scale. That’s power only. Add another dollar or two for 10/100 PHY.
The trick is as others have said in what adding it to your design does in terms of complicating compliance design.
PoE power supplies need to be isolated (except in rare exceptions) and handle much higher voltages than common USB-C or wall wart power supplies.
They have to use a transformer and a more complex control strategy, not a simple buck regulator with an inductor. PoE inputs need to tolerate voltages several times higher than the highest USB-C voltages, so more expensive parts are used everywhere.
Any Ethernet (well, any RJ45 you expect in a home/office) has to have at least 1500V isolation from the RJ45 wire to anything metal that can be touched or is a connector on the device.
A PoE-only device with no electrical connectors besides the RJ45 can just use a very cheap RJ45 port with integrated magnetics and PoE allowance (tiny bit bigger wires and a center pin exposed, less than 50ct more than the cheapest RJ45 with integrated magnetics) and a cheap buck from 40~80V to e.g. 5V.
Oh, and a cheap bridge rectifier and some signaling resistors to take care of input polarity and signal to the source that we in fact want the approximately 50V that could hurt a device not made for it.
That’s not a cheap buck lol. Order of magnitude more expensive then 12v not even mentioning capacitors that can withstand 80v is $$$ and your derating goes to shit
It sounds like the PoE spec was designed before the arrival of “IoT” type things like the esp32, raspberry pi’s, etc.
How much of the complexity is a “fundamental electrical engineering problem” and how much of it is just a spec written to solve a different set of problems?
Almost all of the complexity of PoE is fundamental. To get enough power over 100m of ethernet cable (10x longer than USB) you have to run at much higher voltages like 48V. The same has eventually come to USB: for USB-C Pd to reach 240W, it also has to use 48V.
There have long been lower-voltage "passive PoE" systems which expect a lower always-on voltage on some of the ethernet pairs (usually 12V, 24V, or rarely 48V), which can be very easy to implement so long as your users can handle the setup and incompatibility with other ethernet devices (in the most extreme case of passive PoE on 100Mb/s ethernet, you simply connect the positive pair to the input of the device and the negative pair to the ground, no additional hardware needed).
Whenever you combine two things into one, the complexity and cost go up considerably. A regular coffee machine is pretty cheap. Add high pressure so it can make espresso and it gets considerably more expensive. Add milk so it can make cappuccino, again more complex and expensive. The same holds for electronics. Isolating power when it's alone is fairly straightforward. It gets considerably more tricky and hence more expensive the moment you want to place any kind of a meaningful data signal in its vicinity.
Can't you run a 5V supply from where your router is all the way to every god damn device in your house, and then pretend the wifi is also going through it? If you just want it to be inconvenient, there's no reason to let a lack of PoE stop you!
> You don't need long cables, just a local power source
Which means batteries that have to be replaced and maintained or cables... So ethernet with PoE or even better SPE (single pair Ethernet) with PoDL (power over data lines which is PoE for SPE) is the best from my point of view
I mean, if I just look at my house. There is just one ethernet outlet, but many power sockets. If I want to connect devices all over my house, the best way is to use wifi and usb power adapters. Not ethernet.
Both solutions require 1 cable per device, but the first solution would require only short and thin cables, and the second solution would require very long cables which I don't know even how to do properly without milling my walls.
Yep. Mains electricity is ubiquitous, highly interoperable, very reliable, very high power available per drop, can be outdoor capable, common standards, understandable by users, requiring no active components, with many on-call experts available who can come to fix problems or extend/alter connectivity. Mains power wall plates with inbuilt USB power outlets are even available at quite small cost if the look of the bigger plug and wiring is not appealing.
PoE is much fewer of those things. Difficult to recommend it these days with wifi being fast and reliable and so widely used. Certainly not for average residential user.
That's half the equation. The other half is the reliability and security of wifi, which is less than that of ethernet for people without physical access to my wall innards
Reliability of wifi is not as good I guess, although these days it is extremely good for decent devices. For poor quality devices, I have also heard of PoE routers blowing ports and devices that don't work properly.
Is security of wifi an actual practical concern? I've not heard of it since WPA2.
For average residential user, even most hobbyist / enthusiast, I doubt those things will matter. Almost everybody who wants extremely fast reliable wired connectivity will be much better off using fiber, and using wifi for cameras and automation and streaming and other such things. Getting power to where you need it is not the difficult part, especially if you're pulling wires anyway, which is why PoE has always been fairly niche.
Pretty niche requirement for personal user though. Protection against eavesdropping is the main thing required, and PoE is actually much worse for that than WiFi is you have any drops in less secured ares (e.g., outdoor cameras).
I can see that. I have security devices on my network (e.g. a camera), so I might come at this with a different perspective (since it's not uncommon for burglars to jam wifi).
On the other hand, _all_ the WiFi devices that I had at some point fell off the network, at least once. Including doorbells and cameras. While PoE devices just work.
Another point is that mains power in my area can go down periodically. My PoE switch is powered by a Li-Ion UPS and can provide power for about a day.
> On the other hand, _all_ the WiFi devices that I had at some point fell off the network, at least once. Including doorbells and cameras. While PoE devices just work.
I've not had that in a decade, and only for really shitty devices. I've also had crappy PoE devices stop working, ports blow. Too much effort to be worth the bother for me nowadays. If I had to bet my life sure I'd probably use wired ethernet. But if I had to bet my life I wouldn't be using PoE for power either.
UPS is entirely possible to do on residential mains circuits.
> I've not had that in a decade, and only for really shitty devices. I've also had crappy PoE devices stop working, ports blow.
Every ESP32-based WiFi device _will_ at some point get stuck in the disconnected state. It's almost an ironclad guarantee.
> UPS is entirely possible to do on residential mains circuits.
Sure, but then you're getting into the "whole house" backup with subpanel, transfer switches, etc. You can install backup for your router as a small UPS, but then I also have cameras, doorbells, sensors, etc.
If you already have a house without Ethernet wiring, then opening up the walls just to run PoE makes no sense. But if you're building a new house or if you have pre-existing wiring (and a lot of newish houses do), then PoE is a no-brainer.
> Every ESP32-based WiFi device _will_ at some point get stuck in the disconnected state. It's almost an ironclad guarantee.
See earlier note about crappy devices.
> Sure, but then you're getting into the "whole house" backup with subpanel, transfer switches, etc. You can install backup for your router as a small UPS, but then I also have cameras, doorbells, sensors, etc.
Well you can get small UPS for them too, but sure there are probably some points you can find around your corner of the envelope where PoE makes sense. That's not where many people are though.
> If you already have a house without Ethernet wiring, then opening up the walls just to run PoE makes no sense. But if you're building a new house or if you have pre-existing wiring (and a lot of newish houses do), then PoE is a no-brainer.
Not many new houses do at all because it costs money nobody really wants to pay. A builder will put some in if you ask but not off their own bat because they think it'll make the house worth more, because it won't. So unless some super nerd like your or I ask, no houses will be wired for ethernet. There was a brief window where wifi was non-existent or pretty slow and terrible where it got slightly popular, but that's long past.
If I was building a new house I would wire ethernet from a small server room/cupboard to just several places for wifi APs, plus ethernet and fiber from there to office. No PoE, they would all have USB-C power from same/adjacent wall plate as ethernet. And would probably look at solar+battery system with UPS capability, especially if I lived somewhere with shitty mains power. But even that is not appropriate for normies. They'd just buy a few mesh/repeater wifi things, not care that much about power going out once every few years, and be done with it.
Sure, they're so far up in Germans automakers asses, they don't know it any other way.
One of the reasons i quit my 20 year+ membership with them.
I mean - have some bias? Fine with me, i can read between the lines. Come up with ridiculous crap and reasons to favour domestic brands? There is a line, at least for me and many others that do know when they're intentionally ignoring, downrating, downplaying etc. etc. etc.
Another example? German IT magazine "c't" by heise recently featured a test (4/2026, page 16ff.), in cooperation with ADAC, about subscriptions in electric vehicles - actually one thing where Tesla shines (it's a flat 10€ per month, other countries get a 99$ a year deal) - others don't even bother listing prices until you order, for example.
With no single word that test mentioned Tesla (yet, priding themselves having queried 16 brands for information) - only in the final table overview, there indeed is one column for them.
The bias is showing, it's ridiculous and they can, as far as i'm concerned, go the way of the dodo.
Having added Hisense to my shitlist of TV manufacturers a long time ago - did they ever make a model that haven’t had its power supply die after about 4 years? I don’t think so…
Totally reminded me of the old meme "i accidentally a coca cola bottle, is that bad?" :D
To be more on topic: yup, Casio fx-85ES - still going strong, needs basically no maintenance at all and having tactile buttons you can mash while sitting over a piece of paper just has no comparison.
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