Can BeagleBone Black only be powered by using PoE? In my project I want to avoid using too many cables. So the possibilty to use one cable for power and data would be very interesting. In this case a network switch would be working as an injector. The BeagleBone Black would only receive power from the Ethernet Port without using the 5V DC Port or microUSB Port. If PoE is not available by default, are there possibilties to upgrade by using a cape or an additional circuit?
Yes, if you add it externally and regulate the voltage to 5V and if it can deliver the current. POE is not built into the BBB so you must apply power via the 5VDC port. You can find injector boards at several different places
There may be a cape for this, but I am not aware of one. Adding it externally is a lot simpler.
This simple injector from adafruit might work. It's not full POE compliant though, so probably won't work in long cable runs. http://www.adafruit.com/products/435
Thank you, guys! You helped me a lot
C3-Wireless has developed a fully 802.3af-compliant PoE cape as part of an internal project. We are trying to determine if there is enough demand to release it as a commercial product. We would need to build a minimum of 1000 units to make the price affordable. Do you think crowd-funding would be a good approach? I’d love some feedback at firstname.lastname@example.org. (Mods, please delete if you consider this spam. Thanks.)
Remember that there are two forms of PoE. One is the full architected
802.3af version, which is 48V with a handshake to establish things like
current requirement, and then there is the simpler "passive" PoE which
just pushes typically 12-24V over the power pins (+ is 4-5, - is 7-8).
The PoE pins on the BBB (if I remember correctly) are not used as PoE
and are either grounded or connected to ground by a resistor, either way
However you can get PoE injectors such as:-
The one on the left would be used to power a BBB and the one on the right
would be used to inject the 5VDC into the cat-5 cable.
However be careful as voltage drop across cat5 is bigger than one might
imagine, so you would be better putting 12VDC into the injector and then
connecting a 12V - 5V converter (either a car USB adapter or one of the
little DC-DC converter modules) and pluging that into the BBB as it will
be a "better" 5VDC.
We have launched a BBB PoE cape here, it will be available for sale soon: https://www.n-fuse.co/devices/SBCPoE-BBB-Power-over-Ethernet-Cape-for-BeagleBone-Black.html
If you want one, you can contact me.