This is the desk push-button controller for the transmission light.
There are a series of buttons built into the desk now where the director/producer/whoever can press the button and change the status of the light without typing in any address, all of it is handled by the Raspberry Pi.
Please note, the 5V input is plugged into the USB midro B port on the Raspberry Pi and there is an ethernet cable plugged in, due to the limitations of the software I am using, this cannot be properly represented.