The very first thing we need to decide is in which platform of hardware we are going to develop our project. I decided to use routers because they are cheap an run an entire operating system. I started this project four years ago so routers was and still are a very  good way to develop. 

openwrt is one of the most popular firmware for linux embedded developers because it is very customizable. for the router choosing I choose la fonera 2201 because I need small size and at leas 4 gpios free and ethernet and serial. Four years ago it was one of the best choices