A LoRa-based IoT Sensor Node for Waste Management Based on a Customized Ultrasonic Transceiver

This paper discusses the use of an integrated ultra-sonic transducer for the realization of a LoRa-based Smart Binarchitecture, to be employed for waste management in the SmartCities context. In particular, the paper analyses the usabilityof waterproof ultrasonic sensors for the measurement of wastelevel inside a trash bin: in this context, a solution is describedto increase the directionality of the sensor. Indeed, ultrasonicsensors used in common off-the-shelf waterproof ranging systemsare characterized by a wide radiation lobe, corresponding to anaperture angle up to 70◦: this means that, when employed intrash bins, these sensors detect the presence of the lateral surfaceof the bin and are not able to detect the garbage layer top orits position in the bin. In this paper we propose a tailored cap,designed to be mounted on a commercial ultrasonic sensor, ableto reduce the detection angle down to around 28◦degrees. Themodified sensor can thus be exploited in this application.The proposed sensing structure is integrated into a sensor nodeprovided with a LoRa transmission module, that allows to employit for the development of city-scale monitoring infrastructures.