POE Splitter for ESP8266 on unifi passive 24v POE

Hello community,

I currently use an ESP8266 DevKit board as enOcean gateway that is connected via WiFi. Since the WiFi connection is not available 24/7 I intend to switch to a wired LAN connection instead. A serial connection to the OH machine I not really an option since the gateway would be too far away from my sensors then.

Since I use the micro usb port for powering the device I was thinking about using a POE splitter like for example this one: https://www.amazon.de/dp/B08HS5FSFM/ref=cm_sw_r_cp_apa_glt_i_HMRBK9DX0EPYC764JK3A?_encoding=UTF8&psc=1

However: I have no idea if

  1. One of these splitters works with a passive 24v output of a unifi Poe injector that I have lying around here.
  2. I can get an Ethernet connection to an esp8266 from these splitters
  3. There would be an easier or more straightforward approach in solving this problem (like e.g. a cheap repeater device)

So far I could not find any splitters specifically designed for 24v input. I thought maybe some of you have experience with this?

It might kinda-sorta work, but I would not trust it ever. Or might just never work. Small potential of overheating.
Don’t make problems for yourself, just do it right and use matching stuff to begin with.
A proper 48V PoE switch is not that expensive, and if this project is a success you’re future proof against the next.

Nope, it’s a dumb power splitter. Ethernet signalling is just passed through.
As I understand it you need an ethernet shield for the ESP.

RS485 is long range serial, but you’d need adaptors and choose some serial comms system. Might as well go ethernet.

Your injector is probably IEEE 802.3at compliant so that spitter would be useless.

If you are going to wire it and you just want something that works like your dev board you can get ESP32 boards with POE

Something like


Thank you for your replies. Just one correction: I meant “NONE of these…” instead of “One of these…” I would not want to risk using non matching equipment, don’t worry :wink:


Yeah now that you mention it it is quite obvious that this cannot be the solution :grinning:

Thank you I’ll have a closer look. However this would require me to port the software i’m using to the esp32. Though I maybe might be able to do it I don’t intend to spend too much time on this so I’ll have to see whether this is a road I want to take. However I do not need POE, this was just a matter of making it more convenient.

I thought about that already but I don’t know whether I would still be able to connect my enoceanPi module then.

EDIT: I ordered some W5500 Ethernet shields now and I will try to get this running on an esp32. I will post my results here. Thanks again for your help!

Not likely. the PoE 802.3af standard requires certain signaling to determine the power classification needed for the device. ( max power range 4 W - 15.4 W).

Just a short update if anyone is interested:

I got my gateway working now with an esp32 and a w5500 shield. It was not to much coding to switch from an esp8266 and from WiFi to Ethernet so it worked pretty smoothly.

Now I think I should be practicing my non-existent soldering skills to make this a bit more robust :grinning_face_with_smiling_eyes:

Is it possible that the use of the Ethernet shield can have a significant negative impact on the reception quality of the antenna of the enoceanPi shield?

I hardly receive any signals from the above floor anymore which was working fine with WiFi.