In this paper, we discuss the development of a low cost sensor unit for the monitoring of nitrogen dioxide (NO2). The developed sensor unit can operate at 267.21 mW and collect NO2 concentration, temperature, and relative humidity. The sensor unit was installed outdoors near a main road, for a 122 h experiment. The data collected from the sensor unit were stable. Further, the selected electrochemical NO2 sensor was effective, confirming that NO2 concentrations were high on weekdays (during heavy traffic) and low at night.

Our research group is currently focused on research and development of Internet of Things-based robust emergency and disaster prevention systems to transmit tsunami information retrieved from infrasound sensors. To constantly test the effective sensor operation, it is necessary generate infrasound. Therefore, we considered the infrasound generated when opening and closing doors in this study, and used one sensor to detect the state variation of multiple doors. We constructed and verified the detection system for various doors.