Pressure-Activated RF Sensing: A Smart Cushion Approach for Energy-Efficient IoT Health Monitoring

The growing elderly population has spurred the development of innovative technologies to monitor their health and support independent living. Radiofrequency sensors have gained traction for noninvasive measurement of age-related parameters. Their unobtrusive nature allows seamless integration into a person’s living environment. However, a drawback of radiofrequency sensors lies in their constant connection to vector network analyzers, leading to unwanted noise and readings when no one is present. This study introduces a novel device employing radiofrequency-based sensors, operating within the 800 MHz to 2.5 GHz range, connected to a vector network analyzer. A matrix of pressure-based sensors was integrated into a cushion to activate the vector network analyzer. Experiments involved the researchers sitting on the cushion, which triggered the analyzer to capture readings from an antenna sensor placed on a phantom mimicking changes in body dielectric properties. Results demonstrated the system’s ability to detect changes in the phantom’s body dielectric properties effectively only when it is activated (i.e., person sits on the cushion). Furthermore, a comparison between the collected reflection coefficient data and that of a regular vector network analyzer revealed no discernible differences.