The desire for persistent, long term surveillance and covertness places severe constraints on the power consumption of a sensor node. To achieve the desired endurance while minimizing the size of the node, it is imperative to use application-specific integrated circuits (ASICs) that deliver the required performance with maximal power efficiency while minimizing the amount of communication bandwidth needed. This paper reviews our ongoing effort to integrate several micropower devices for low-power wake-up detection, blind source separation and localization and pattern classification, and demonstrate the utility of the system in relevant surveillance applications. The capabilities of each module are presented in detail along with performance statistics measured during recent experiments.
Simultaneous mapping of multiple electrical or chemical properties of
neural activity facilitates understanding neurological phenomena and
their underlying mechanisms. We present a track-and-hold potentiostat
performing simultaneous acquisition of 16 independent channels of
current ranging five orders of magnitude in dynamic range over four
scales down to hundreds of picoamperes. Sampling rate ranges from DC
to 200KHz. The system features programmable current gain control,
configurable anti-aliasing log-domain filter, triggered current
integration and provides differential output ready for asynchronous
external analog-to-digital conversion over a compressed dynamic range.
We present system description, circuit implementation and experimental
results of real-time neurotransmitter concentration measurements from
the 16-channel prototype fabricated in a 1.2 micron CMOS process.