An instrument scheduler design for energy neutral coastal monitoring systems deployment
Yuting Zhang, Thomas D. C. Little, Benjamen R. Wetherill, Francesco Peri, Robert F. Chen · 2014
Advances in computing, communications, and sensor technologies are creating new opportunities to exploit low-cost instrumentation for widespread and long-term environmental observation. Because a tethered energy infrastructure is usually not available at these remote locations, localized energy harvesting and power management must be employed for the perpetual energy-neutral operation at low cost with low maintenance. Our strategy is to schedule instruments wisely to execute the sensing mission during the targeted periodic or sporadic events, and to 'sleep' or turn off whenever else for energy conservation. In this paper we present the design of a programmable instrument scheduler that works with an Arduino for power management based on real time clock (RTC). The instrument scheduler allows the duty cycle of power-intensive sensing components at arbitrary schedules in the Arduino software. The current circuit hardware is capable of switching four power channels, including one for itself. This instrument scheduler has been used in several practical deployments to control an ecological observation platform of video cameras and wireless networking equipment. The erosion monitoring platform was implemented at the Thompson Island (Boston, Massachusetts, USA) in October 2012 and at the Jones River watershed (Kingston, Massachusetts, USA) in September 2013. Both systems have been in operation as designed since installation, and are expected to continue operating indefinitely. The deployed systems demonstrate how duty cycling can achieve substantial energy savings on a diverse set of devices through complete shutdown. This approach is expected to have wide applicability for a variety of environmental and ecological studies.