In this paper, we propose a new kind of WiFi-based embedded device and two power efficient killer applications on it. First, the definition of our pervasive device and the key challenge research issues on it is introduced. Then we specially present our work on it, including hardware and software part. For hardware part, we will show our new Loongson SOC (system on a chip) chip based hardware architecture, which is power efficient and flexible connective interface one. For software part, we focus on two killer applications for this kind of pervasive device: location estimation and video codec. The power aware method we used in above two applications will be introduced in detail.