Implementation of a Low-Cost Energy and Environment Monitoring System Based on a Hybrid Wireless Sensor Network

A low-cost hybrid wireless sensor network (wsn) that utilizes the 917 mhz band wireless smart utility network (wi-sun) and a 447 mhz band narrow bandwidth communication network is implemented for electric metering and room temperature,humidity,and co2 gas measurements. a mesh network connection that is commonly utilized for the internet of things (iot) is used for the wi-sun under the contiki os,and a star connection is used for the narrow bandwidth network. both a duty-cycling receiver algorithm and a digitally controlled temperature-compensated crystal oscillator algorithm for frequency reference are implemented at the physical layer of the receiver to accomplish low-power and low-cost wireless sensor node design. a two-level temperature-compensation approach,in which first a fixed third-order curve and then a sample-based first-order curve are applied,is proposed using a conventional at-cut quartz crystal resonator. the developed wsn is installed in a home and provides reliable data collection with low construction complexity and power consumption. © 2017 dong sik kim et al.