We started this project, to make it much quicker and easier to build smart home prototypes around Arduino processors. This simple board does plugs into the bottom header on the Arduino Mega 2560 and exposes three 10-Way DIL connector. It uses our standard set of connectors and pin designations. It also includes an LED and resistor which we use to indicator errors.

We don't have to fully populate the header board with components. We often only install the parts required for each specific application. For example, this board is being used for our conservatory irrigation system. It is very easy to add more components later if required.