Set for release during the summer, the PoE HAT was announced alongside the Raspberry Pi 3B+ model, but little was known about it. That is until a listing was added to the Farnell website (they’re a Raspberry Pi Foundation partner) where the device is now available for pre-ordering.
But what is a Power-over-Ethernet HAT?
Mounted on the GPIO, the PoE HAT is designed to supply power to the Raspberry Pi 3B+ (and any later devices) via an Ethernet cable. Ideal for Internet of Things and embedded projects, this removes the need for a separate power supply and ensures that a fast, reliable, wired internet connection is simultaneously available.
Listed at just £17.75 (inc VAT), the HAT also appears to have a controller for the fan, which will probably be a software option, rather than a physical switch. However, there is a physical dimension to the HAT that you may need to plan for. We won’t know until the device is officially available, but there has been some suggestion that the PoE HAT isn’t compatible with some Raspberry Pi 3B+ cases.
Eben Upton, founder of the Raspberry Pi Foundation, has observed that some cases may have issues if designers make assumptions about the z-height of points over the surface of a Raspberry Pi 3B+. One of these points could easily be the 4-pin PoE header; just as easily, however, it could be components intended for thermal coupling with the processor, which is now larger (on the z-height axis) than in previous models.
This comes hot on the heels of news that some pre-existing HATS are apparently incompatible with the new Raspberry Pi 3B+, necessitating some unexpected third-party hardware revisions.
Meanwhile, if you’re using a different model of Raspberry Pi, don’t feel left out. Several suppliers stock alternative Power-over-Ethernet HATS for older versions of the popular SBC.