High Sensitive Sensors to Measure Hand and Foot Sweat for Noninvasive Health Monitoring

In this article, we design and implement effective sensors to measure the amount of sweat on the fingertips, palms of hands, and foot soles. The proposed structures use different patterns for sensor electrodes to achieve a highly sensitive pattern. By measuring the amount of sweat on the fingertips, palms, and soles, it is possible to study the effects of drugs and the presence of diseases such as stress, hyperhidrosis (HH), and diabetes. For this purpose, it is vital to have a sensitive and accurate sensor to measure the amount of sweat on these body parts. The tips of the fingers, palms of hands, and foot soles may have less sweat; in this case, only a high-efficiency sensor can sense this low sweat. A high-sensitivity sensor is more accurate at measuring the desired parameter. Therefore, in this article, we will design five resistive sensors on the printed circuit board (PCB). We have only investigated the effect of the proposed structures for implementing a resistive sensor to design an effective and sensitive sensor. To measure the amount of sweat, the sensors are <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 3$ </tex-math></inline-formula> cm (a small sensor for fingertip sweat) and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$29\times 13$ </tex-math></inline-formula> cm (a sensor for soles and palms). Also, the amount of sweat is visually indicated through several light-emitting diodes (LEDs) based on a proposed low-cost circuit. In addition, as an example, a structure has been designed to provide the numerical value of the amount of sweat. Sensitivity analyses are performed to evaluate the performance of the structures. The results show that the proposed structures provide an acceptable sensitivity for noninvasive health monitoring.