Mark Weiser, noted computer scientist and father of ubiquitous computing, once observed about the field that, "applications are of course the whole point." The proposed research seeks to push the frontiers of knowledge to enable some of the applications that he, and others like Kris Pister (who coined the term "Smart Dust"), envisioned would become possible when perpetual, cubic-mm, wireless sensor nodes transitioned from science fiction into reality. If this is realized and adopted by the sensor network community, many new and exciting applications will be realized by the research community years ahead of market forces. The goal of this project is to develop a complete wireless sensing and computing node that includes a low-resolution imager, signal processing and memory, temperature sensor, on-board CMOS timer, wireless communication, battery, and solar energy harvesting that are all packaged in a 1mm3 volume through low-cost die stacking and encapsulation.

We proposed a 1.0mm3 general-purpose heterogeneous sensor node platform with a stackable multi-layer structure that includes a new, ultra-low power I2C (Inter-Integrated Circuit) interface for inter-layer communication. The system has an ultra-low power optical wakeup receiver, GOC (Global Optical Communication), which allows for re-programming or synchronization. It also includes an ultra-low power PMU (Power Management Unit) with BOD (Brown-Out Detector) to prevent processor malfunctions and battery damage, and also controls POR (Power-On Reset) modules in other layers to enable a proper reset sequence. Image and temperature sensors are implemented, but the modularity of the system allows end users to easily replace or add layers to incorporate specific circuits in appropriate technologies as needed.