In this presentation we overview the Sensor network research being conducted at the Wireless and Mobile Networking Lab at BU. Sensor networks have a number of unique features that make them different from conventional networks, or even wireless multi-hop networks. Their application-specific data-driven nature, their limited resources, and the need for collaborative distributed operation present a number of challenges to building such systems. We overview these challenges, and then present a sample of our work in the areas of routing, storage and security. We also briefly discuss our research testbed.