We’re always on the lookout for neat solutions to everyday maker type problems. One of the problems that makers often run up against is how to supply power to a board that needs to be sited in a location away from power sockets; for example a weather station or wildlife camera.
The Pi PoE (Power over Ethernet) Switch HAT (http://cpc.farnell.com/pi-supply/poe-switch-hat/pi-poe-switch-hat-for-raspberry/dp/SC14178) provides an excellent solution to this very problem for the Raspberry Pi. The Pi PoE Switch HAT is a Power over Ethernet add-on board for the Raspberry Pi, allowing the Pi to be powered using a single Ethernet cable.
The Pi PoE Switch HAT simply sits on top of the Raspberry Pi GPIO pins, requires no additional software, and can be fixed in place using the supplied nylon standoffs and screws. There is also a short RJ45 patch cable provided, to connect between the Ethernet ports on the Switch HAT and the Raspberry Pi. The board also features an extended GPIO header, meaning that the GPIO pins are still available for use to connect external circuits or to mount further add-on boards.
Once mounted on the Pi, an Ethernet cable must be run into the PoE socket on the Pi PoE Switch HAT. As well as carrying data to the Pi, this Ethernet cable will also provide the power supply for the Pi. However, in order to do so the other end of the Ethernet cable needs to be connected to either a network switch that supports PoE, or to a PoE injector. For our testing, we opted for a basic PoE injector (http://cpc.farnell.com/tp-link/tl-poe150s/adaptor-poe-injector-100m/dp/CS21284). The following image shows our completed setup. Although we only used a short (approximately 1m) Ethernet cable for our setup, the PoE injector should support a cable of up to 100m in length; so it’s ideally suited for that bird box Pi camera at the end of the garden.