The Energy Endoscope: Real-Time Detailed Energy Accounting for Wireless Sensor Nodes

This paper describes a new embedded networked sen-sor platform architecture that combines hardware and soft-ware tools providing detailed, fine-grained real-time en-ergy usage information. We introduce the LEAP2 plat-form, a qualitative step forward over the previously devel-oped LEAP [13] and other similar platforms. LEAP2 is based on a new low power ASIC system and generally appli-cable supporting architecture that provides unprecedented capabilities for directly observing energy usage of multi-ple subsystems in real-time. Real-time observation with microsecond-scale time resolution enables direct account-ing of energy dissipation for each computing task as well as for each hardware subsystem. The new hardware archi-tecture is exploited with our new software tools, etop and endoscope. A series of experimental investigations provide high-resolution power information in networking, storage, memory and processing for primary embedded networked sensing applications. Using results obtained in real-time we show that for a large class of wireless sensor network nodes, there exist several interdependencies in energy con-sumption between different subsystems. Through the use of our measurement tools we demonstrate that by carefully se-lecting the system operating points, energy savings of over 60 % can be achieved while retaining system performance.