We Makers know the issue, with one board we can either have a simple and effective sensor/actuator control (Arduino) or a powerful platform for applications (Linux with Rpi). The truth is WE NEED BOTH and today this means two boards in most cases. And possibly more when WiFi is needed.
There are many boards available but usually it is not possible to reuse our arduino shields due to the different voltages (5v/3.3v) as well we need to adapt our very simple and effective arduino code to a more complex linux device.

Facing this issue many times I decided to design a board that allows me to have a cheap arduino like board with wifi and linux power. Mica7688 is a completely opensource project based on the mediatek 7688 processor.
In order to support the wider variety of Arduino projects, I made two version which are identical except for the micro controller. The MiCa7688 Uno comes with an ATmega 328P and the MiCa7688 Mega with an ATmega 2560.