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.

In Japan, more than 1,000 earthquakes occur annually, thus causing enormous damage. However, in areas facing the ocean, the risks of secondary disasters due to tsunamis are extremely high. We conducted research the on an emergency disaster prevention system for transmitting tsunami information using ultra-low- frequency sound sensors and tide-level gauges. The system conveyed the information to members in the crisis management staff for the area concerned, and we assumed that the staff in charge made evacuation recommendations to the citizens of the area based on the information. In addition, when a tsunami occurs, there is a high possibility that an existing infrastructure cannot be used because an earthquake has already occurred. In this research, we develop a disaster prevention system using tsunami information using long-distance wireless communication technology, MAD-SS.

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.

In this study, we conducted long-distance radio propagation experiments at 1mW/145 MHz to realize low-power long-distance communication for wildlife research and disaster prevention telemetry [1]. We successfully realized long-distance communications from a weather balloon (elevation: ~14,000 m) with 1 mW radio power. Furthermore, we demonstrated that our method can achieve such long-distance communication at 10 BPS/1mW with battery cell operation in the SSB mode and that the SNR in the SSB bandwidth is better than -10 dB.

We conducted long distance radio propagation experiments at 1-10mW/145MHz, to realize a low-power long-distance communication for wildlife research and disaster prevention telemetry. In this paper, we describe that we succeeded in long distance communications, from a ferryboat to the top of Mt. Asugiyama (elevation: 501m, distance: 15km) in Kure, Hiroshima, Japan, in the verification test of our method using 3W radio power. We found out that our method has sufficient capability to achieve such a long distance communication at 10BPS/10mW in battery cell operation on a marine, if we use SSB mode and the SNR in SSB bandwidth is better than -10dB.

In this paper, we describe the construction of a long distance communication sensor network node for Arduino. We develop a Mad-SS Shield prototype system, which succeeds in about 5-km transmission with a 1 mW output.