The development phase started long time ago. Initially I wanted to use an esp8266 to manage a display and input sensors. It had WiFi and it could be perfect for what I needed. I started to design a board  around the ESP-12 module but the ESP don't have enough gpios for my needs. (Displays uses SPI busses and a lot of lines to control)

At that point I was starting to design a proper board size, here in italy the electronic stuff is inserted into 503 boxes. The sizes are small but not that small!

Now I moved to a ATmega 328P, and I decided to add an IO header to add more functionality later. The module have acces to all most important gpios of the ATmega like interrupts and serial. On the back of the baseboard an header is used to connect to the front board with the most important stuff :)