Accurate Battery-operated IoT sensor for detecting combustible gas leaks in homes

This paper presents a novel battery-operated IoT sensor node tailored for the accurate detection of combustible gas leaks in residential environments. Integrated with innovative sensor technologies, i.e. micromachined membrane pellistors and with low-power VOC sensors, the device ensures efficient gas monitoring. The electronics was designed with low power circuitry and in such away as to be versatile with respect to the power supply. Powered by Lithium Thionyl Chloride batteries guarantees an energy self-sufficiency longer than one year. It also permits to significantly further prolong this lifespan, by exploiting a novel measurement policy based on sensor triggering. Upon detecting odorizer concentration exceeding a threshold, based on VOC concentration continuous monitoring, the device activates the pellistor for combustible gas detection. The proposed approach minimizes power consumption and maximizes responsiveness, extending the device's lifespan significantly. Additionally, the device utilizes LoRa and BLE connectivity, transmitting data to a LoRa remote gateway daily under normal conditions, increasing the transmission data packet rate during gas leak events and allowing for prompt BLE local interrogation. Given the application context, linked to the measurement of gas concentrations well under the lower explosive limit, the sensors adopted in the device were characterized starting from gas mixtures with known concentrations, showing performances adequate for the application context.