Autonomous Wearable System for Vital Signs Measurement With Energy-Harvesting Module

The growing demand for wearable devices is imposed by the ability to monitor in real-time critical situations in the different areas of daily life. In many cases, power is the limiting factor for such devices. One aspect is the power supply with batteries that introduces issues due to the weight, the overall dimensions, and the disposal of the batteries. A viable solution to overcome the limitations of batteries as power source is to harvest ambient energy to power the devices directly. In this paper, a proposed wearable device with an energy-harvesting module has been designed, manufactured, and tested for the measurement of vital signs. The energy-harvesting module is implemented to directly power the electronic circuit board by a flexible solar panel. This paper describes the proposed instrumented autonomous T-shirt powered by the flexible solar panel applied directly on the T-shirt. The instrumented T-shirt is capable of measuring respiration rate, heart rate, and movement of the body. The methodology adopted, the design choices, and the experimental results are clearly reported and discussed. The experimental results show the functioning even with poor outdoor lighting conditions and under specific indoor constraints. Tests have been conducted aiming to compare the instrumented T-shirt's output data with the data obtained via instruments as gold standards and to show that the overall system described in this paper is capable of producing reliable data compared with the data obtained with these instruments.