Automatic, Smart, Safe, and Battery-Less Environment Monitoring With IoT: Communication, Localization, and Sensing

This paper presents an automatic, smart, safe and battery-less network for environmental monitoring implemented by passive Internet of Things (IoT) sensing devices with an Ultra High-Frequency (UHF) Radio Frequency IDentification (RFID) interface. A mobile robot navigates into the environment enabling continuous and automatic communication with passive RFID sensor tags deployed at specified locations and their localization as well. These low-power sensors, identified through the tag Electronic Product Code (EPC), may provide temperature, humidity, lighting, or other data through the RFID standardized communication protocol. To enhance the system degree of automation, passive RFID tags implementing antenna self-tuning strategies are also exploited by the robot to identify obstacles in the environment by exploiting the same mobile RFID architecture used for environmental monitoring. Fine-grained positioning of passive RFID sensors is achieved with techniques based on the Synthetic Arrays principle. The paper presents a demonstrator illustrating the described system. It includes passive RFID sensor tags designed for indoor temperature monitoring, with a moving antenna featured to localize the sensor tags and detect self-tuning tags installed for the collision-avoidance system. The performance confirms the practicality of the proposed IoT system.