A Bluetooth-based Sensor Node for Low-Power Ad Hoc Networks

TCP/IP has recently taken promising steps toward being a viable communication architecture for networked sensor nodes. Furthermore, the use of Bluetooth can enable a wide range of new applications, and in this article, an overview of the performance and characteristics of a networked sensor node based on TCP/IP and Bluetooth is presented. The number of Bluetooth-enabled consumer devices on the market is increasing, which gives Bluetooth an advantage compared to other radio technologies from an interoperability point of view. However, this excellent ability to communicate introduces disadvantages since neither TCP/IP nor Bluetooth were designed with resource-constrained sensor nodes in mind. We, however, argue that the constraints imposed by general purpose protocols and technologies can be greatly reduced by exploiting characteristics of the communication scheme in use and efficient and extensive use of available low-power modes. Furthermore, we claim that a Bluetooth-enabled networked sensor node can achieve an operating lifetime in the range of years using a total volume of less than 10 cm. The Mulle Embedded Internet System (EIS), along with its advanced power management architecture, is presented as a case-study to support the claims.