The Orange Pi Zeros spec sheet states it supports PoE, which it does, but not without a little work! If you were hoping to buy the board, put an OS on an SD card and plug it in to your PoE switch, then you might be a little disappointed to find nothing happens.
This is because the Orange Pi Zero does not support standard 24v or 48v PoE, instead it supports firing 5v into the Ethernet jack via the standard PoE pairs.
To achieve this, you need to do two things.
- bridge a pair of pads on the back of the board with solder or wire
- Find a way to reliably get 5v to the Ethernet jack
Assuming you have a soldering iron around and a steady hand, number 1 is easy. Number 2 might need a little thought though since voltage drop is a factor when dealing with long cable runs. That means if you feed 5v in to one end of a 100 meter Ethernet cable and try to run your board off that, well, it almost certainly wont because if you measure the voltage at the board end, you will find it will have dropped far below 5v.
The simplest way to work around voltage drop it to feed the cable with a higher voltage and use a regulator at the boards end to drop it to a clean 5v supply.
- You need to do a bit of soldering on the back of the board – if you get it wrong, its possible to kill the power supply or the orange pi board.
- You will be connecting half of the pairs of wire in the Cat5 cable to the 5v supply of the board. I would suggest you don’t plug the board into the network with a regular cable and plug 5v into the micro USB connector once the pins are connected because you might break the network kit or your power supply.
I used the following:
- Standard solid core Cat5e cable
- RJ45 crimps
- A 5v 3amp step down converter
- A 12v 3.3amp power supply salvaged from an old laptop
- A pair of salvaged 2pin connectors for the PSU end
Step 1 – Prepare the board
There are four small pads which are disconnected to begin with. This is good really because it stop the board from frying if plugged in to regular PoE at its higher voltage!
The pads can be found on the bottom of the board:
These need to be joined horizontally with the board oriented in the same was as these pictures like so:
Take your time – any shorts here could destroy your PSU or Zero board!
If you are interested, the pair nearest the 26pin header is ground and the other pair is hooked up to the 5v input.
Step 2 – Prepare the cable
I stripped the end of the cat5 as though I were going to make a standard cable up, but stripped much more of the outer insulation than normal to allow me to cut down the green and orange pairs (which are used for data) to normal length, and leave a loop of the blue and brown pairs……
…so I can splice the regulator in….
Using T-586B standard (like most cables will be), both of the brown pair will be your negative side, then the blue pair will be +5v at the board side.
I then did a similar thing at the other end of the cable, wiring the brown and blue pairs to a connector for the laptop PSU and making the sure the side of the pairs in the RJ45 crimp aren’t shorting to anything.
I then tested everything with a multi meter looking for shorts, and testing the output of the regulator. Once it was all looking good, I used liberal amounts of heat-shrink to protect and tidy, plugged it all in and the board fired up!
- You could use a pre-made cat5 cable and carefully extract the blue and brown pairs (like I did a the PSU end) so you don’t have to buy a reel of Cat5 and termination kit. You will need to be careful when peeling back the insulation though – you don’t want to cut the pairs with a knife etc!
- All this really achieves is to use two pairs of Cat5 which is unused for 100mbps connections to send power down. These is no reason why you can’t also use this method but break the board end out to a micro USB cable to power your Raspberry Pi or other boards.
- This is quite a clumsy way to do PoE – if the cable is already run, you need to mess about with attaching regulators etc in situ – this would be fiddly if you were mounting this on the ceiling for example.
- You could just buy pre-made injector/splitter cables but that would be no fun would it?!