A novel sweat rate and conductivity sensor patch made with low-cost fabrication techniques

Sweat sensor patches offer new opportunities for unobtrusive monitoring of an athlete's physical status. This paper presents a novel sweat rate and sweat conductivity patch that is easy to prototype and can be made with common low-cost production techniques: laser cutting and standard printed circuit board (PCB) manufacturing. The device consists of a patch made from hydrophilic PET foil, a double-sided adhesive and a thin PCB with gold electrodes. Two electrodes, which are continuously in contact with the inflowing fluid, measure the sweat conductivity and a separate system with interdigitated electrodes measures the filling process of the reservoirs. Impedance measurement results of both systems demonstrate the working of the concept.