This work presents neMEMSi, a novel MEMS based inertial and magnetic system-on-board with embedded processing and wireless communication capabilities, providing an ultra low-power and easy to use Attitude and Heading Reference System (AHRS). Main target applications are navigation systems and inertial based motion tracking technologies. The paper describes the architecture of neMEMSi and provides an evaluation of the performance in terms of key features of state-of-the-art AHRS.