Very nice alternative for both abovementioned master computers is GIGABYTE BRIX Pro. It can serve booth as onboard integrated computer powered from mobile platform batteries, as well controller for standalone Emys, powered from dedicated external AC power supply. Required input voltage is 19V from at least 65W power supply. Computer physical paramaters are:
The computer is presented in Fig. 1, whereas its external I/Os are presented in Fig. 2. Detailed information about the computer can be found here LINK.
Fig. 1 GIGABYTE BRIX Pro.
Fig. 2 External I/O.