Some sensor network elements for ubiquitous computing

Ubiquitous computing applications often use a user´s context to automatically adjust their behavior to the situation. We have developed three types of wireless sensor nodes that can be worn, carried, or embedded in the environment that can provide interesting contextual information: a rich multi-sensor node to infer human activity that can be worn by a person or be part of a sensing environment, a portable wireless node for reading and writing short-range radio-frequency identification (RFID) tags, and a small wrist-watch-sized wireless display device that can serve as an easily accessible and ´glanceable´ user interface. We report on our experiences in building these platforms and using them in some initial applications. We conclude with suggestions for future work in creating platforms that help blend sensor networks into ubiquitous computing.