Introducing PoE HAT
On sale 8/24/2018
Yesterday, Raspberrypi.org finally announced the release of the POE HAT, a way over powering your Raspberry Pi over Ethernet. The Raspberry Pi 3b+ was originally released with the ability to be Powered over Ethernet (PoE) with a HAT. The HAT was released 8/24/2018. The PoE HAT is a small accessory for the Raspberry Pi 3 Model B+ (released March, 2018). For this product to be used, the network it is connected to needs to have power-sourcing equipment installed.
Purchase from Canakit.com
Supplied with this product
- Raspberry Pi PoE HAT
- Mechanical spacers
Other hardware needed
- A Raspberry Pi 3 Model B+
- An Ethernet cable
- Power-sourcing equipment for a 802.3af Power over Ethernet network
- Provided by your network switch
- Or power injectors on an Ethernet Cable
Power Over Ethernet
Power over Ethernet places power on the Ethernet cable along with the data. A couple methods of this has been standardized back in 2003, and is widely adopted. PoE has no effect on the data, so you won’t lose bandwidth. There are various standards of PoE; this HAT uses the most common standard 802.3af. This standard provides up to 15 W of DC power (minimum 44 V DC and 350 mA) on each port. Only 12.95 W is assured to be available at the powered device as some power dissipates in the cable
This means that the HAT is capable of providing all the power needed for running your Raspberry Pi! You will need power sourcing equipment to power your Pi. This is either provided by your network switch or with power injectors on an Ethernet cable.
Using the PoE HAT
- Before installing the PoE HAT, you must attach the supplied spacers in the four corners of the board
- Then connect the Raspberry Pi PoE HAT to the two 0.1” headers (40 + 4) that are fitted on the Raspberry Pi
- Once the PoE HAT board is connected, you can power the Raspberry Pi through its RJ45 network connector
The HAT is a compact, single-sided board that sits within the footprint of the Raspberry Pi. A small (25mm) fan is pre-installed on the board. The HAT could be useful to people building systems that could be in tougher environments, so the addition of the fan helps with cooling. The fan is controlled via a small ATMEL processor which allows for it to be temperature-controlled: when your Raspberry Pi processor hits certain temperatures, the fan automatically turns on to cool it down. To enable this you will need to get the latest firmware (sudo rpi-update).
Because the fan is controlled over I2C, none of the GPIO are used, so you can stack a second HAT on top of the connector. To do this you will need to buy some longer pass-through headers that expose the pins on the other side of the PoE HAT. You will need one for the 40-way and one for the 4-way connector that has the PoE splitters on it.