Where's the mote? Ask the MoteHunter!

Contrary to laboratory environments, real-world wireless sensor network deployments face harsh conditions where motes can be lost during deployment or in operation, for several reasons. Motes mounted on animals can easily detach. Fixed motes could get displaced by environmental conditions, e.g., heavy rains. These motes could contain valuable data and/or equipment, but finding them out in the wild could be quite challenging. Similar challenges arise in the cases where the placement of nodes is not known a priori, and yet in-field interaction with them (e.g., for data downloading or debugging) is needed. We present MoteHunter, a tool supporting in-field searching for motes, composed of: the Hunter, a special node with custom hardware and software and equipped with a directional antenna, and the Prey, which can be in principle any mote compliant with IEEE 802.15.4, although a special small-footprint software component can be integrated with the application to simplify the search. We illustrate the architecture of MoteHunter and discuss our design choices quantitatively and qualitatively.